Drinking water
2014
Public water supplies in the
London and South East region of England
July 2015
A report by the Chief Inspector of Drinking Water
Drinking Water Inspectorate | Nobel House, 17 Smith Square | London | SW1P 3JR | Tel: 0300 068 6400
www.dwi.gov.uk
London and South East region
Drinking water 2014
London and South East
region of England
1
Drinking water 2014
P ub l is he d b y
Dri nk i ng W ater Ins p ec tor at e
Ar ea 7e
9 M i ll b a nk
c /o N o be l H ous e
17 Sm it h S qu ar e
Lo n do n
SW 1P 3J R
T el: 0 3 00 06 8 6 4 00
W ebs ite : ww w. d wi . def r a. g o v. uk
© Cr o wn Co p yr i gh t 2 0 1 5
IS B N : 97 8- 1- 9 0 58 5 2- 8 8- 8
Co p yr i gh t i n th e t yp o g r ap h ic a l ar r an g em ent an d d es ig n res ts wi t h t he Cr o wn .
T his p ub l ic at i on ( ex c lu d in g t he lo g o) m a y b e rep ro d uc e d f r ee of c h a rge in an y
f orm at or m ed i um pr o v i de d t ha t i t is r e pr od uc ed ac c ur at e l y a n d no t us e d i n a
m is le a di n g c o nt ex t . T h e m at er ia l m us t b e ac k no wl e d ge d as Cr o wn c op yr i g ht wi th
th e t it l e a nd s o ur c e of th e p ub l ic at i on s pec if i ed .
2
London and South East region
Contents
Chapt er 1: Summar y
4
Chapt er 2: W ater supply arrangements
10
Chapt er 3: Drinking water qualit y test ing
14
Chapt er 4: Drinking water qualit y results
4.1 Microbiological qualit y
4.2 Chem ical qualit y
19
34
Chapt er 5: Drinking water qualit y events
58
Chapt er 6: Technical audit activit y
71
Annex 1:
Further sources of inf or mation
77
Annex 2:
Guidance and resear ch published by DW I
78
Annex 3:
Drinking water qualit y events in the region
80
Annex 4:
Planned drinking wat er qualit y improvements
120
Annex 5:
Compet ition in the water industr y
124
Annex 6:
W ater company indices
126
Annex 7:
Cost recover y
129
Annex 8:
Glossar y and description of standards
130
Annex 9:
Looking af ter water in your home
143
Drinking water 2014 is the annual report of the Drinking Water Inspectorate and
c o mp r i s e s r e p o r t s c o v e r i n g p u b l i c a n d p r i v a t e w a t e r s u p p l i e s .
Public supplies – This part describes drinking water quality in the London and South
E a s t r e g i o n . T h e I n s p e c t o r a t e a l s o p u b l i s h e s a s e r i e s o f c o mp a n i o n r e p o r t s f o r o t h e r
regions of England (Central and Eastern, Northern, and Western regions) and a
separate report for Wales.
P r i v a t e s u p p l i e s – A s u m ma r y o f i n f o r ma t i o n o n p r i v a t e w a t e r s u p p l i e s i s r e p o r t e d f o r
England and Wales.
A l l p a r t s a r e a v a i l a b l e o n t h e I n s p e c t o r a t e ’s w e b s i t e w w w . d w i . d e f r a . g o v . u k
3
Drinking water 2014
Chapter 1: Summary
Chapt er 1:

Provides a summar y of the report f or the London and South East
region.

Puts drinking water qualit y in the region into context nat ionally.
Drinking water 201 4 is the annual publication of the Chief Inspector of
Drinking W ater f or England. It is the 25 t h report of the work of the
Inspectorat e and pr esents inf ormation about drinking water qualit y f or the
calendar year of 201 4. It is published as a series of seven reports, of
which f ive cover public water supplies and two describe privat e water
supplies. This report is about public supplies in the London and South East
region of England .
Set out in this report are the key f acts about the qualit y of the public water
supplies in the London and South East r egion, which is ser ved by nine
water companies deliver ing supplies to 19 million consumers. The area
ser ved by each water company is shown in Figure 1 and the organi sat ion
and nat ure of water supplies in the London and South East r egion is
descr ibed in more detail in Chapter 2: Water supply a rrangem ents. Four
new inset appointments began supplying water in the region during 2014.
SSE W ater commenced suppl ying three development s: Heart of East
Greenwich in East London; Nine Elms, Battersea in London ( a merger of
two inset appointments ) and Hill s Farm Lane in Horsham, W est Sussex ;
and Albion W ater commenced a supply in a development called Rissington,
near Bourton-on-the- W ater in Gloucest ershire.
There were changes also in the number of private water supplies in the
region not if ied by local auth or ities to the Inspectorate in 2014 with the
total decreasing to 2,598 f rom 2,699 in 2013. Det ailed inf ormation about
the regulat ion and qualit y of private supplies can be f ound in the separate
report entit led Drinking water 2014 – Private water supplies i n England.
The qualit y of public water supplies in England in 2014 was good with only
0.05% of tests f ailing to meet the European Union ( EU) and national
standards. This com pares f avourably to t he 1.6 % of f ailures recorded in
1991, the f irst year af ter pr ivatisation of the water industr y, when
regulation of drinking water qualit y was f irst introduced. The situat ion in
relat ion to the quality of private water supplies in England remains less
satisf actor y with 6% of tests f ailing to meet the EU and nat ional standards
in 2014. However, this f igure compares f avourably to the 7.5% of tests that
f ailed in 2010, the year when new regulations implement ing the EU
Drinking W ater Directive f or private supplies were introduced.
4
London and South East region
Figure 1: Water suppl y arrangement s
The results of testing of public supplies in 201 4 demonstrated that overall
the qualit y of drinking water in the London and South East region was
good. The f igure f or compliance with dr inking water standards was 99.96%,
down f rom the regional f igure of 99.97% in 2013, and above t he industr y
average (99.95%). The Inspectorate uses a range of indices t o assess the
water qualit y perf ormance of the companies providing public supplies.
5
Drinking water 2014
These indices 1 look in turn at water treat ment (process control and
disinf ectio n indices), service reser voir int egrity and net work maintenance.
Individual water company f igures are set out in Annex 6. In 2014, in the
London and South East region , there was an improvement in the
disinf ection f igure with no change f or the other three i ndices (process
control, net work maintenance and ser vice reser voir integrit y ), with all the
f igures at or above the industr y average.
Figure 2 shows an improvement in the disinf ection index up from 99.97% in
2013 to 99.98% in 2014, which is attr ibut able t o a general im provement f or
Aff init y W ater and f ewer colif orm and tur bidit y f ailures at works operated
by Sout h East W ater and Thames W ater (31 in 2013 compared to 18 in
2014) partially of f set by the decline in Southern W ater’s perf ormance in
2014 with col if orm and turbidit y f ailures at f ive works.
Figure 2: Company performance for the disinfection index
Across the London and South East region , in 201 4 there were more events
aff ecting drinking water qualit y reported t o the Inspect orate (149 compared
to 106 in 201 3) with 90 (60%) classif ied as minor or not signif icant
(compared to 53 (49%) in 2013 ).
However, in 2014 there were more (six) serious events compared to none
in 2013. T wo of these serious events were linked to the severe weather in
the early part of the year where f looding threatened t wo water treatment
works: Kenley works operated by Sutton and East Surrey W ater ser ving
1
C a lc u l at i on m et ho d f o r i n d ic es is p ub l is he d at
ht tp :/ /d wi . d ef r a. g o v. uk /a b ou t/ a nn u al - re p ort /c a lc u l at i ng - i n d ic es .p df
6
London and South East region
consumers in W arlingham and surrounding area s, and Egham works
operated by Af f inity W ater supplying consumers in Surrey and area s to the
west of London. There were also three events involving the detection of
Cryptosporidium oocysts in treated water that occurred during the same
spell of severe weat her , one of which was classif ied as ser ious
(Hambleden works operated by Thames W ate r). Two ser ious events
reported in 2014 wer e due to the detection of colif orms in treated water at
Kangley Bridge works, operated by Tham es W ater and the oc currence of
the disinf ection byproduct chlorat e in wat er supplied f rom Southern
W ater’s W eir W ood works. The Inspector ate has taken enf orcement action
in the f orm of Notice s in relat ion to t wo of these events ( W eir W ood (see
Chapt er 5: Drinking water quality events and Annex 3) and Kangley Br idge
(see Chapter 4 – Coliform bacter ia at works and Annex 3)). The sixth event
occurred at Streatley service reser voir in Reading involving a petrol tast e
and odour (see Annex 3).
There were no prosecutions brought by t he Inspectorate in 2014 f or any
companies operat ing in the London and South East region.
Local aut horit ies across England and W ales provided case st udies on the
remediation of f ailing privat e water supplies. Three examples relat ing to
the London and Sout h East region can be f ound in Dr inking w ater 2014 –
Private water supplies in England – Chapter 3: I mproving private water
supplies.
More inf ormation and industr y - wide learning points about these and other
signif icant events can be f ound in Chapter 5: Drinking water quality event s
and a summar y of all signif icant events in the region can be f ound in
Annex 3 of the report.
Table 3: Water qual it y events in 2014
Nat ur e of ev e nt
Ce ntr a l a n d E as t er n
Lo n do n a n d S ou t h E as t
Nor th er n
W es tern
W ales
Indu st r y
Ri sk as s es sm ent cat ego r y ( DW I)
M inor*
Si gnif i ca nt
S er iou s * *
20 1 3
20 1 4
20 1 3
20 1 4
20 1 3
20 1 4
10 7
11 9
49
59
1
5
53
90
53
53
6
18
28
47
48
1
39
32
41
53
2
9
13
11
10
22 5
28 1
19 9
21 8
3
12
F i ve e ve n t s a f f e c t e d t w o o r m o r e r e g i o n s i n 2 0 1 4 a n d t wo i n 2 0 1 3 .
* Mi n o r c a t e g o r y n u m b e r s i n c l u d e a l l n o t s i g n i f i c a n t a n d m i n o r e ve n t s .
* * S e r i o u s c a t e g o r y n u m b e r s i n c l u d e a l l s e r i o u s a n d m a j o r e ve n t s .
During 2014, the Inspectorate carried out 497 audits of water supply
arrangements in England and W ales and 123 of these were in the London
and South East region with thr ee being unsatisf actor y.
7
Drinking water 2014
W hen consumers are dissat isf ied with the qualit y of their dr inking water
they may contact their water company. Records of the number s of contacts
received by water companies are sent to the Inspector ate each year. In the
London and South East region the total number of cons umer contacts to
water companies about the qualit y of drinking wat er was 1 contact per
1,000 populat ion, f ewer than the industr y average of 1.7 contacts per
1,000 populat ion. If the water company f ails to address the consumer’s
water qualit y issue, t he con sumer can seek assistance f rom the
Inspectorat e. In 201 4, the Inspector ate investigated 39 consumer
complaints of which 10 (4 SRN, 3 SEW , 2 TMS, 1 IW N) were in the London
and South East region.
Also, during 2014, the Inspector ate handled 374 requests f or a dvice about
private water supplies f rom local authorit ies across England and W ales
and 94 of these enquir ies were f rom the London and South East region.
Audit f indings and consumer complaint case examples can be f ound in
Chapt er 6 – Technical audit activit y and details of the work of the
Inspectorat e in relat ion to private supplies can be f ound in the companion
report entit led Drinking water 2014 – Private water supplies in England.
Turning to planned improvements in dr inking water qualit y in the region,
during 2014 the Inspectorate conf irmed the need f or improvements at the
f ollowing locat ions t o address a range of def iciencies ident if ied through
audits or events dur ing the year :

Kangley Bridge, Bedwyn and Hambleden works operated by Thames
W ater to address treatment def iciencies.

Ventnor and W eir Wood works operated by Sout hern W ater, the f irst to
address secur it y risk s and the second to address treatment
def iciencies.

Speen works oper ated by Thames W ater to address f ault y pr ocess
monitor ing instrumentation at this and all other sim ilar sites . The
necessar y works wer e completed at all sit es by the end of December
2014.

Hardham works oper ated by Souther n W ater to address turbidity and
other vulnerabilities of the drinking water treatment caused by def ects
associated with the sludge handling, waste water treatment, chlor ine
dosing and dechlorination equipment . These impr ovements to the
treatment works wer e completed bef ore the end of 2014 , however the
need f or f urther work has been ident if ied and the Notice may be
revised.
Additionally, as part of Of wat’s pr ice review process, 27 legally-binding
Notices and undertakings wer e put in place by the Inspectorate in
response to companies’ business plan pr oposals f or the price setting
8
London and South East region
period Apr il 2015 to March 2020 ( A MP6). These require companies to
address a range of risks to drinking water qualit y such as lead,
metaldehyde, nitrate, colif orm bacteria and Cryptospor idium ( see Annex
4).
Companies in the region are committed to complete all the planned work
summarised in Annex 4 by the dates shown. Most schemes in the region
are proceeding in line with agreed timescales , however, f ive schemes ( 2
AFW , 1 SRN and 2 TMS) have been delayed f or a var iet y of diff erent
reasons (see Annex 4.1).
By way of comparison, in 201 4, local aut horit ies in the London and South
East region put in place 49 improvement Notices in relation to f ailing
private water supplies.
In 2014, the Inspect orate provided the water industr y with technical advice
on six topics to enable water suppliers to co mply with the drinking water
regulations. The Inspectorate also provided technical advice on t wo topics
relat ing to local authorities in relation to private water suppl ies. In
addition, f our research projects were commissioned by the I nspector ate to
develop underpinning knowledge f or regulator y r isk assessments. Annex 2
lists all of the advice and research published by the Inspect orate in 201 4.
Annex 9, ‘Looking after water in your home’ , provides advice f or
consumers, recently updated and published by W ate r UK.
This is the second year f ollowing the intr oduct ion of the cost recover y
f unding arrangements f or the Inspectorate , whereby the costs of regulating
public water supplies is f unded by water suppliers rather than the
taxpayer. Annex 7 sets out the regul at ory costs incurred by each public
water supplier in 2014/15. From this it can be seen that the Inspectorate
recovered a total of £1,994, 880 in 2014/ 15 . This compar es to a total of
£1,977, 541 in 2013/ 14.
In June 2014, the Secretar y of State appr oved the Chief Inspector’s
proposal not to amend the charges f or 2014/15, ther ef ore the daily charge
out rate f or each of the f our regulator y activit ies was the same f or both
years (see schedule at http://dwi.def ra.gov.uk/stakeholders/ inf ormation letters/2013/03- 2013-schedule- 2014-15.pdf ). The main dif f erence bet ween
the years is ref lected in the charges f or audits, events and consumer
complaint investigations which are risk -based.
9
Drinking water 2014
Chapter 2: Water supply arrangements
Chapt er 2:

Identif ies the water supply compani es in the region .

Illustrates the water source and supply ar rangements in the region .

Provides summary f igures describing the water supply assets and
stakeholders.
Figure 4: Map illust rating sources of drinking w ater by zone across
the region
Nine water companies supply dr inking water in the London and South East
region: Af f inity W ater (AFW ); Portsmouth W ater (PRT); South East W ater
(SEW ); Southern W ater (SRN); Sutton and East Surr ey W ater (SES);
10
London and South East region
Thames W ater (TMS); and three inset appointees, SSE W ater (SSE),
Independent W ater Net works Ltd (IW N) and Albion W ater (ALB).
As shown in Figure 1, SSE W ater already supplied water to insets in Hale
Village in Tottenham, London; Kennet Island in Reading; Bromley Common
in south east London; Park Views in Epsom; Grayling well Park, Chichester;
Great W estern Park, Didcot; Kingsmere in Bicester; New Sout h Quarter in
Croydon; Mar ine W harf , Deptf ord, southeast London; and Newlands,
W aterlooville, near Portsmouth. Dur ing 2014, SSE began supplying water
to additional de velopments as f ollows: Heart of East Greenwich, London ,
Hills Farm Lane, Hor sham , and Nine Elms, Battersea in London.
Independent W ater Net works Ltd supplies water to the Br idge in Dartf ord,
Berr yf ields in Aylesbury and the Kings Cross development in Londo n. Also
during the year, Albion W ater commenced suppl ying 875 consumers in
Upper Rissington, near Bourton - on-the-W ater in Gloucestershire . One
f urther appointment granted in 2014 did not commence supply during the
year ( Millennium Village, IW N).
Just over one half of the water supplied in the region or iginates f rom
surf ace water ( 54%) abstracted f rom lowland rivers such as the Thames,
Eden, Cher well, Great Stour, Itchen, Medway, Ouse, Test and the River
Yar on the Isle of W ight. Most river wat er is held in large, raw-water
storage reser voirs bef ore being drawn off f or treatment. Reservoirs like
Farmoor (Oxf ord) and Bough Beech (Edenbridge) are strategic reser ves
replenished over the winter and drawn down in summer. W ater is also
drawn f rom two large, interc onnected com plexes of impounding reservoirs
to the south west and north of London. O ther reser voirs in the south of the
region are Ar dingly, Arlington, Bewl, Dar well, Powdermill and W eir W ood.
A signif icant amount of the water supplied to consumers in the region,
particularly those living outside London, is derived f rom groundwater
(44%) with most boreholes drawing water f rom the chalk aquif ers of the
North and South Downs, and the oolitic limestone or greensand aquif ers
f ound across the region. South East W ater abstracts f rom the Ashdown
sandstones to supply the W eald area. In Kent, Af f inity W ater relies
exclusively on groundwater, mostly f rom the chalk aquif ers, with the Denge
peninsular dependent on a shallow gravel aquif er.
Figure 5 illustrates the location of privat e and public supply groundwater
abstraction points in relat ion to the groundwat er aquif ers in t he region.
11
Drinking water 2014
Figure 5: Location of private and public suppl y groundw ater
abstraction point s
N o t e : M a p e xc l u d e s s u r f a c e i m p a c t e d g r o u n d w a t e r , s u c h a s we l l s a n d s p r i n g s .
Summar y f acts about the drinking water supply inf rastructure of the region
are given in Table 6 with outline geographical and demographic
inf ormation.
12
London and South East region
Table 6: Key fact s about the London and South East region suppl y
arrangements
Public supplies
Private supplies
Population supplied
Water supplied (l/day)
Abstraction points
Treatment works
Service reservoirs
Water supply zones
Length of mains pipe (km)
18,884,729
4,927 million
725
427
1,072
521
84,303
Water composition
Surface sources
Groundwater sources
Mixed sources
54.5%
43.5%
2%
Population supplied
Water supplied (l/day)
Approximate number of private
water supplies*
Total number of local
authorities
Number of local authorities
with private supplies
Water composition
Surface influenced supplies
Groundwater sources
Mains water
Unknown
122,873
56 million
2,598
112
79
27%
68.5%
4%
0.5%
Area of supply
Berkshire (part), East Sussex, Hampshire (part), Isle of Wight, Kent, Surrey, Bedfordshire
(part), Buckinghamshire (part), Essex (part), Gloucestershire (part), Hertfordshire, Inner
London, Outer London (part), Oxfordshire, West Sussex, Warwickshire (part), Wiltshire (part)
*Boundaries for public supplies regions are based on groupings of water company zones.
Boundaries for private supplies figures are based on the closest approximation of the public
supply zones. Where local authorities boundaries cross regional boundaries, the whole local
authority data has been attributed to the region in which the majority of its area lies.
13
Drinking water 2014
Chapter 3: Drinking water quality testing
Chapt er 3:

Explains the basis of the drinking wat er testing programme.

Recor ds the number of tests carried out by water companies.

Identif ies any def iciencies in water test ing and how these have been
remedied.
Throughout 2014, water companies sampled drinking water across the
region to ver if y com pliance with the dr inking water regulations. Almost half
of the tests were carried out on samples drawn f rom consumers’ taps
selected at random. For monitor ing p urposes, company water supply areas
are divided into zones. Sampling in zones at consumers’ taps is risk -based
with the number of tests being higher in zones with a large population
(maximum 100,000). Other sample locat ions are water treatment works and
treated wat er (ser vice) reser voirs. Collectively, the nine water companies
carried out a total of 1,150,224 tests dur ing 201 4 and only 287 of these
tests f ailed to meet one or more of the standards set down in the
Regulations or exceeded a screening value.
14
London and South East region
Table 7: Number of tests carried out by companies in the region
Pl a ce of s a mpl ing
Comp an y
W at e r
t r eat me nt
w ork s
Af f in i t y
W ater
S erv ic e
re s e rv oi rs
Con sum e rs ’
tap s
(z one s)
Numb e r of
T arg et
tes ts p er
com pa n y
numb e r of
tes ts
52 , 15 6
( 96 )
36 , 78 5
( 14 5)
76 , 72 6
( 76 )
16 5 ,6 6 7
16 5 ,7 6 6
0
( 0)
0
( 0)
35 6
( 1)
35 6
35 6
A lb i o n
W ater
In d ep e nd e nt
W ater
Ne t work s
P orts m ou th
W ater
0
( 0)
0
( 0)
1, 1 75
( 3)
1, 1 75
1, 1 75
11 , 79 1
( 19 )
9, 4 65
( 31 )
17 , 64 6
( 13 )
38 , 90 2
38 , 95 8
S ou th E as t
W ater
77 , 43 6
( 96 )
69 , 09 3
( 23 9)
77 , 91 5
( 72 )
22 4 ,4 4 4
22 7 ,8 8 5
S ou th er n
W ater
53 , 98 7
( 89 )
60 , 68 0
( 20 0)
93 , 38 2
( 74 )
20 8 ,0 4 9
21 3 ,8 2 4
0
( 0)
0
( 0)
5, 8 44
( 13 )
5, 8 44
5, 8 46
S S E W ater
S ut to n a nd
E as t Sur r e y
W ater
T ham es
W ater
12 , 96 6
( 7)
8, 4 65
( 32 )
16 , 45 9
( 20 )
37 , 89 0
37 , 89 0
11 0 ,3 3 6
( 95 )
94 , 95 5
( 38 0)
26 2 ,6 0 6
( 24 9)
46 7 ,8 9 7
46 8 ,1 8 8
Reg ion
ov er a ll
31 8 ,6 7 2
( 40 2)
27 9 ,4 4 3
( 1, 0 27)
55 2 ,1 0 9
( 52 1)
1, 1 50 ,2 2 4
1, 1 59 ,8 8 8
Note: Numbers in brackets reflect the number of works, reservoirs or zones operated by t hat
company in the region in 2014. Some companies are permitted to carry out some tests on
samples taken from supply points rather than from consumers’ taps.
The Regulat ion s set out the parameters water companies must test f or and
most of the t esting is f or parameters wit h a European or national standard
(Schedule 1 par ameters) , however, water companies are also required to
test f or other indicator parameters (Schedule 2 paramet ers). The
Regulations also lay down how many of these tests must be done f or
samples collected f rom each t ype of sample point ever y ye ar (Schedule 3)
and the Inspectorat e checks that the wat er companies ar e meeting these
sample f requencies.
In 2014, across the industr y the Inspectorate f ound f rom its checks that
there was a shortf all in the number of test results submitted by eight
companies. The extent, scope and reasons f or the shortf alls ar e present ed
in Table 8 and the f ollowing industr y wide summary is provided f or
lear ning.
15
Drinking water 2014
Three companies ( SEW , SRN, SVT) wer e f ound to have large shortf alls. In
relat ion to Southern W ater this was m ainly due to a problem with data
transf er between IT systems (6 ,000 out of 6,608 missing test results) ,
however, the company also f ailed to provide accurat e population data f or
zones in the annual return setting out the planned sampling programme in
advance. The correct population dat a was resubmitted and this reduced
the shortf all to under 6,000 tests. Dat a was subsequently submitted to the
Inspectorat e in March 2015. South East W ater had a shortf all of close to
5,000 test results due to various f ailings i n the management of the
sampling programme (inaccurate ‘asset out of service’ inf ormation and
samples either not being taken or results not being included in data
returns to the Inspectorate ). However, there was also a f undamental f law
in the company’s ret urn wher eby the nitr ate/nitr ite calculat ion by its
laborator y was wrong, impacting on both its returns and also those
provided by other companies using its laborator y. Subsequent correction of
out of service inf ormation reduced the shortf all to 3,441 tests . Severn
Trent W ater’s shortf all of 1,000 test results was also due to failings in the
management of the sampling programme. Looking across all the
companies wit h shor tf alls , collect ed sam ples being ‘lost in the process’
bet ween receipt by t he laborator y a nd reporting of the results back to the
company was a common problem, which in the case of W essex W ater
accounted f or one -third of its shortf all.
Companies must plan and provide to the Inspectorat e an annual sampling
programme bef ore the start of each yea r. However, dur ing the year, wher e
an asset is taken out of service the scheduled sampling program me will
need to be revised t o show that the num ber of expected sam ples f rom this
site has changed. The Inspector ate is concerned to note that many
companies ar e not actively manag ing the sample pr ogram me in a timely or
accurate manner so that appropriat e adjustments in the expected number
of samples are not occurring. Asset out of service inf ormation is crit ical to
the process of shortfall checking, theref ore c ompanies should be using this
inf ormation act ively and ensuring it is correct when it is pr ovided to the
Inspectorat e in the June and December compliance returns. The accur acy
of this data is crucial to the summary and shortf all calculat ions processed
within the Inspectorate ’s reporting system s. Senior managers should
understand that those companies that f ail to actively manage their
sampling program me are providing f alse inf ormation to the Inspectorate
(and onwards to the public and the European Commission ) and also
displaying a lack of care about the wat er qualit y perf ormance of the
company. For both t hese reasons, the Inspectorate rem inds senior
managers that they should be taking steps to satisf y themselves , through
regular internal reports , that the reg ulatory sampling program me is being
actively managed and the systems in place are f it f or purpose and
adequately resourced.
16
London and South East region
Table 8: Shortfalls i n tests submitted t o the Inspectorat e
Comp an y
D ŵr C ym r u
W els h W ater
Is su e w it h t est d ata
S hor tf a l l i n tes t n um be rs a t
v ar io us d if f er e n t t yp es of
s am pl e p oi n t ( 26 7) .
Nor th um br ia n
W ater
S e ve n a d di t io n a l da t a
s ubm is s i ons of d at a f o r 2 0 14
m ade i n M ar c h 20 1 5.
S e ver n T r en t
W ater
S hor tf a l l i n tes t n um be rs
( 1, 0 73) af f ec t in g 8 4
par am et er s f r om al l t ype s of
s am pl e p oi n t.
S ou th E as t
W ater
S hor tf a l l i n tes t n um be rs
( 4, 7 02) af f ec t in g 8 6
par am et er s f r om al l t ypes of
s am pl e p oi n t.
S ou th er n
W ater
T ham es W ater
Un i te d
Ut i l it i es
Ni tr at e/ n itr i te c alc u l at i on b y
c om pan y’ s la b or at or y
i nc or r ec t f or d a ta r et ur ns
c o ver i n g p er i o d M a y 2 01 3 t o
Fe br u ar y 2 0 15 (t h is im pac t ed
on ot her wa ter c om pa n ies
us in g t he s am e l a bor a tor y) .
S hor tf a l l i n tes t n um be rs
( 6, 6 08) af f ec t in g 1 12
par am et er s f r om al l t ypes of
s am pl e p oi n t.
Re a son s
- Sc he d u le d s am pl es n o t
c o ll ec te d.
- Err ors i n t he s c h e du l e .
- La b or at or y is s ues .
- Inc orr ec t ‘as s et ou t of
s er v ic e inf orm ati o n ’.
- For p es t ic i de par am et er, a n
i ns tr um ent f a i lu re in t h e
l ab or at or y wa s no t i d e nt if i e d
un t i l af ter t h e ye a r e n d.
- La b or at or y is s ues ( AQ C an d
eq u i pm ent f a i lur es ) .
- La b or at or y is s ues
(eq u i pm ent a n d AQ C
f ai l ures , n on - ac c r e di t e d
m etho d us e d f or o n e
par am et er).
- S am pl er err ors .
- Sc he d u li n g err ors .
- Inc orr ec t ‘as s et o u t of
s er v ic e inf orm ati o n ’.
- S am pl es c o ll ec te d b ut
res u l ts n ot i nc l ud e d o n d at a
ret ur n to I ns pec t ora t e.
- Sc he d u le d s am pl es n o t
c o ll ec te d.
-
S hor tf a l l i n tes t n um be rs (2 9 1)
f or a l l t yp es of p ar am eter a n d
s am pl e p oi n ts .
-
S hor tf a l l i n tes t n um be rs (1 9 6)
f or a l l t yp es of p ar am eter a n d
s am pl e p oi n t.
-
-
-
W es s ex W ater
S hor tf a l l i n tes t n um b e rs (2 9 0)
f or a l l t yp es of p ar am eter a n d
s am pl e p oi n t.
-
17
Inc orr ec t p o pu l at i o n d at a
us e d a t s tar t of ye a r.
Da ta ha n dl i n g/ tra ns f er
pro b l em s wi th i n c om p an y
s ys tem s .
La b or at or y a na l ys is n o t
c om pl et e d.
Sc he d u le d s am pl es n o t
c o ll ec te d.
La b or at or y is s ues ( AQ C
f ai l ures , d at a i nt e gr it y
c hec k s ).
Err ors i n r e s c h ed u l in g f or
s am pl es n ot c o l l ec t ed on
or ig i n al s c he d ul e .
La b or at or y is s ues (m a i nl y
an a l ys is n ot c om p le te d).
Inc orr ec t ‘as s et ou t of
s er v ic e ’ inf orm at i o n.
Sc he d u li n g err ors .
Drinking water 2014
The Regulat ion s also require that the water samples are repr esentat ive of
water being supplied to consumers and there are requirements to ensure
the qualit y of the analysis of samples in the laborator y. In 2014 , the
Inspectorat e was not if ied of eight events (1 DW R, 1 NNE, 2 SRN, 1 SSE,
1 SVT, 1 TMS, 1 UUT) where sampling or analysis was not to the required
standard. Of these, the Inspectorate regarded f ive as signif icant. In one
instance, there was an artef act compound identif ied during a pesticide
analysis (SSE), in another case t wo sam ples were swapped within the
analysis process (SRN) , on t wo occasions data was manipulated (DW R
and NNE). In the remaining instance, a sample was collected f rom an out
of service asset (SVT). Further details about these events can be f ound in
Annex 3 of the relevant report .
18
London and South East region
Chapter 4: Drinking water quality results
Chapt er 4:

Provides details of tests f ailing to meet microbiological and chemical
standards.

Comments on the remedial act ion taken by the wat er company or the
Inspectorat e.
The key water qualit y results f or the London and South East r egion are
presented in t wo tables, one showing the results f or microbiological
parameters (Table 9) , the other dealing with chem ical and physical
parameters (Table 1 7). The microbiological qualit y of water is discussed
f irst. Companies report all the resul ts of the tests on a monthly basis to the
Inspectorat e. A sum mary of the results of testing f or all parameters and
tables that descr ibe the drinking water qualit y perf ormance indices of each
company can be f ound on the DW I website ( www. dwi.def ra.gov.uk ).
Microbiological quality
To protect public health, micr obiological standards have to be met at each
individual treatment works and ser vice reser voir. The signif icance of the
individual test results f or each microbiological parameter at each locat ion
var ies and a single posit ive result cannot be int erpreted wit hout other
inf ormation. All com panies are expected to f ollow best pract ice as set out
in The Microbiology of Drinking Water published by the Standing
Committee of Analysts (SCA) which can be f ound by vi sit ing the website at
https://www.gov.uk/government/publications/standing -committ ee-of analysts-sca- blue-books.
19
Drinking water 2014
Table 9: Microbi ological tests
The number of test s performed and the number of tests not meeting
the standard
P ar am et e r
Cu rr ent
st a nd a r d
T otal
numb e r
of t est s
Numb e r
of t est s
not
me eti ng
the
sta nd ar d
Ad di tio na l
info rm at ion
W ate r l e av ing w at e r t re at me nt w or k s
E.c o l i
Co l if orm
bac t eri a
Cl os tri d i um
per fr i ng e ns
T urb id i t y
1
0/ 1 00m l
45 , 26 8
0
0/ 1 00m l
45 , 27 0
11
0/ 1 00m l
13 , 53 7
1
1NT U
48 , 99 6
12
S EW ( 3) , S RN (3) ,
T MS ( 5)
T MS ( 1)
AFW ( 1) , S EW (6),
SR N (2) , T M S (3 )
W ate r l e av ing s e rv i c e r es e rv oi r s
E.c o l i
Co l if orm
bac t eri a
0/ 1 00m l
51 , 21 1
7
0/ 1 00m l i n
95 % of t es ts
at e ac h
r es e r vo ir
51 , 22 4
33
PRT ( 1) , S EW
SR N (3) , T M S
AFW ( 3) , P RT
S EW (6), S RN
T MS ( 1 7)
(1),
(2 )
(1 ),
(6) ,
A l l 1, 0 27 r es er v o irs i n
th e r e g io n m et t h e
95 % c om pl i anc e ru l e
W ate r s a mpl ed at co nsu me r s’ t a ps
E.c o l i
0/ 1 00m l
47 , 38 4
8
E nt er oc oc c i
0/ 1 00m l
3, 9 06
3
1
PRT ( 1) , SR N (1) ,
T MS ( 6)
S EW ( 1) ,T M S ( 2)
Tu r b i d i t y i s a c r i t i c a l c o n t r o l p a r a m e t e r f o r w a t e r t r e a t m e n t a n d d i s i n f e c t i o n .
E.coli at w orks and service reservoirs
In 2014, all the com panies carr ied out a total of 96,479 tests at treatment
works and ser vice reser voirs across the region. E.coli was det ected in no
samples f rom works a nd seven samples collected f rom service reser voirs.
This is an increase in recorded f ailures at these assets compared with
2013, when there were only t wo E.coli f ailures.
On detecting E.coli, companies ar e required to act promptly t o protect
public health. The im mediate response when f inding E.coli at a works or
reser voir is to sample again , and more widely, to conf irm that water being
received by consumers is saf e. In 2014 t here was no wider event
associated with any of the f ailures.
In June, E.coli was detected at Goose Green water tower near Little
Am well in Hertf ordshire operated by Thames W ater. This was notif ied to
20
London and South East region
the Inspector ate as an event and the tower taken out of use (see Annex 3).
The tower has been associated with previous f ailures and events in 2010
and 2013 when an inspection by the com pany f ound no def ects. An audit
by the Inspectorate in July verif ied some potent ial ingress points, although
the roof membrane that was replaced in 2010 was in good condit ion, and
issues with the sampling arran gements and turnover. The tower remains
out of use awaiting repairs and completion of the company’s investigat ion
into the cause of the poor turnover and low chlorine levels.
In December , Thames W ater reported E.coli in a sample taken from
Nunhead Upper reservoir, located in Sout hwark. This was reported to the
Inspectorat e as an event (see Annex 3). The reservoir was taken out of
supply and repairs were carried out, along with upgrading the sampling
f acilit ies. It was subsequently ret urned t o supply in Marc h 2015 and
enhanced monitor ing was put in place.
In September, E.coli was detected in a sample taken f rom Appledown
reser voir, near Havant. Portsmouth W ater reported this to the Inspectorate
as an event (see Annex 3). The investig ation evidence provided t o the
Inspectorat e indicated that the result was not representative of water in
supply because of poor sample handling practice in the labor atory.
Southern W ater detected E.coli in samples f rom three dif f erent service
reser voirs in 2014. In Februar y , an E.coli f ailure f rom Singlewell reser voir
No.1, in Gravesend was attributed to some minor def ects that wer e
repaired and all subsequent results f rom this sit e have proved satisf actor y.
In October, E.coli was detected in samples taken on the same day f rom
High Hat W hitwell reser voirs (No.1 and No. 2), situated near Ventnor on
the Isle of W ight. Although the company undertook repairs at the time the
Inspectorat e recommended that the company replace the sam pling
f acilit ies to ensure t hat they are f it f or purpose.
In September , E.coli was detected in a samp le collected by South East
W ater f rom Godmersham r eser voir near Maidstone and this was not if ied to
the Inspector ate as an event (see Annex 3). The reser voir was taken out of
supply f or inspections and remedial w ork was carr ied out to im prove
turnover within the cell bef ore the reser voir was returned to service in
December.
21
Drinking water 2014
Table 10: Detection of E.coli and Enterococci at treatment w orks,
service reservoirs and consumers’ taps
Comp an y
E. co li i n
w at er
le av in g
t r eat me nt
w ork s
E. co li i n
w ater
le av in g
se rv i c e
re s e rv oi rs
E. co li a t
con su me r s’
tap s
Ent e ro co cc i
at
con su me r s’
tap s
Af f in i t y W ater
0 – 5 ,3 3 9
0 – 7 ,3 5 7
0 – 8 ,4 6 4
0 – 5 72
A lb i o n W ater
0 – 0
0 – 0
0 – 12
0 – 4
0 – 0
0 – 0
0 – 36
0 – 13
0 – 1 ,9 7 0
1 – 1 ,5 8 0
1 – 1 ,8 0 0
0 – 1 17
0 – 1 0, 9 88
1 – 1 1, 5 24
0 – 5 ,4 9 2
1 – 5 77
0 – 7 ,3 1 2
3 – 1 0, 1 00
1 – 5 ,9 3 2
0 – 5 12
S S E W ater
0 – 0
0 – 0
0 – 1 32
0 – 45
S ut to n a nd
E as t Surr e y
W ater
0 – 2 ,0 5 5
0 – 1 ,6 9 3
0 – 1 ,7 0 4
0 – 1 60
T ham es W ater
0 – 1 7, 6 04
2 – 1 8, 9 57
6 – 2 3, 8 12
2 – 1 ,9 0 6
Reg ion
ov er a ll
0 – 4 5, 2 68
7 – 5 1, 2 11
8 – 4 7, 3 84
3 – 3 ,9 0 6
In d ep e nd e nt
W ater
Ne t work s
P orts m ou th
W ater
S ou th E as t
W ater
S ou th er n
W ater
Note: Results are shown as the number of positive tests – the total number of tests.
Coliform bacteria at w orks
Testing f or colif orm bacteria gives reassurance that water entering supply
was treated adequat ely to remove bacter ial and viral pat hogens. Repeated
occurrences of colif orm bacteria in samples f rom the same works in one
year are thus of concern and require act ion to be taken. In 2014, this
situat ion occurred at one sit e: Headley Park works operated by South East
W ater, which supplies Bordon, Haselmere, Tilf ord and the surr ounding
area.
The invest igation of a colif orm f ailur e at Headley Park works in July did
not identif y a cause , however , af ter a second colif orm f ailure in August a
more thorough investigation of the treatment works identif ied potent ial
ingress points in the f inal water contact t ank. Following repair s all f urther
results have pr oved satisf act or y.
Southern W ater decided that a colif orm failure in June at Brede works,
near Hastings was associated with poor sampling f acilities. A number of
other f ailures had recently been attribut ed to the sample arrangements
22
London and South East region
theref ore the Inspect orate has recomm ended a review of the sampling
f acilit ies. Figure 11 shows the improved sampling arrangements now
installed at Brede works.
Figure 11: New sampling taps at Brede w orks
In August f ollowing a colif orm f ailure at Kangley Br idge works in Brom ley,
Kent Thames W ater f ound seepage of rainwater through the roof of the
f inal water tank. This was reported as an event to the Inspect orate (see
Annex 3). There was a previous E.coli f ailure at this site in 2012, af ter
which a Notice was put in place requir ing improvem ents to the f inal water
tank roof . The Inspectorate audited the site in Januar y to ver if y that the
actions in the Notice were complete, and the visible evidence on site at the
time indicated that this was the case. However , the f ailure in August
revealed t he repair was not robust and this has led to a revision of the
Notice to require that maintenance and r epair contractors are proper ly
super vised and that repair works are f it for purpose
Seepage of rainwater through the roof of a f inal water tank was also the
cause of a colif orm failure in October at Thames W ater’s Bishops Green,
near Newbur y in Ber kshire. This was reported to the Inspectorate as an
event (see Annex 3). Repairs to the contact tank have been carried out
and there have been no f urther f ailure s since.
23
Drinking water 2014
Figure 12: Water pooling on t he roof of the final w ater tank of Bishops
Green
Figure 13: Moss and veget ation debris on the roof of the f inal w ater
tank at Bishops Green
Companies are reminded that they should be regular ly inspecting thei r
assets to spot developing issues ear ly, escalating inspection inf ormation
so that senior manag ement is clear about the need to improve planned
preventat ive maintenance.
24
London and South East region
There were colif orm f ailures at a f urther six works during 2014 ( 3 TMS,
1 SEW , 2 SRN) wher e the company f ailed to ident if y a cause. The
Inspectorat e expects companies to implement enhanced sur veillance in
such circumstances.
Notices have been put in place to address microbiological r isks at South
East W ater’s Stockbury works, near Maidst one and W aterworks Road
works, near Eastbourne . Microf iltrat ion is to be installed at these sit es
during AMP6 to ensure that disinf ection is secure , given the evidence that
the microbiological qualit y of the raw wat er is poor.
In April, Southern W ater comp leted a scheme to install a new contact main
at Minster Iot works near Margate and this scheme will ensur e that
disinf ection is more robust benef iting up to 133,000 consumer s in the
Fleete and Rumf ields zones which are served by this and other works .
In summary, the Inspectorate has noted t hat colif orm bacteria were f ound
in 11 samples f rom treatment works in the London and South East region
during the year . This inf ormation will be taken into account during the
Inspectorat e’s r isk -based programme of techni cal audit.
Clostridium perfringens
This organism is a spore-f orming bacterium that is exceptionally resistant
to unf avour able conditions in the water environment, such as extremes of
temperature and pH, and disinf ection pr ocesses such as chlor inat ion and
ultraviolet light. It is a normal component of the intestinal f lora of up to
35% of humans and other warm -blooded animals. These char acterist ics
make it a usef ul indicator of either inter mittent or hist orical f aecal
contamination of a groundwater source o r the perf ormance of a surf ace
water f iltration plant. The detection of any Clostridium perfringens should
trigger an invest igation by the water com pany.
In 2014, out of 13,537 samples taken in t he region, one did not meet the
specif ied value: A sample col lected by Thames W ater f rom a consumer ’s
tap in Newcross zone in July was posit ive f or Clostridium per fringens . The
zone is one of many f ed by the company’s large slow sand f ilt ered surf ace
water works located to the west of London. A Not ice is in place re quiring
the company to ref urbish slow sand f ilter s at one of these works (Ashf ord
Common) by March 2015, although complet ion of the work has been
delayed by three months. Daily sampling f or Clostridium perfr ingens takes
place at all these lar ge works , but to achieve the f requency required by the
EU Dr inking W ater Direct ive the company takes addit ional samples f rom
consumers’ taps. It would be more appr opriate f or these addit ional
samples to be collected f rom other supply points such as ser vice
25
Drinking water 2014
reser voirs to avoid inconveniencing consumers wit h inconclusive plumbing
hyg iene investigat ions, as occurred in this case.
Turbidity at w orks
Turbidit y is a measure of how much light can pass through water and
indicates the ‘cloudiness’ of water. Turbidit y may be cau sed by either
inorganic or organic particles suspended in the water. At a treatment
works turbidit y is an important cr itical control in relation to determining
whether raw water has been adequately prepared f or disinf ection. Turbidit y
standards are set at two points in the wat er supply chain, at treatment
works and at consumers’ taps. The f ollowing discussion f ocuses on the
results of samples taken at treatment wor ks wher e the standar d is 1 NTU.
The results of turbidity test ing at consum er taps can be f ound in the
Maintaining water quality in distribution section.
Groundw ater w orks
W here turbidity arises in groundwater it is usually as a consequence of
disturbance of inert clay or chalk particles , but it can also arise f rom the
oxidation and precipitation of certain inorganic substances like iron and
manganese when air is introduced into the water by pumping. If the
groundwater is under the inf luence of surf ace water then the cause of
turbidit y may be part icles with adherent biological matter, which may
contain pat hogens.
Irrespective of origin, turbidit y can interf ere with the eff iciency of
disinf ection. Turbidit y is theref ore a crit ical control measure t hat should be
validated at a groundwater works by continuous on - line monit oring of raw
water with alarms s et to ensure that act ion is taken to ensure that turbidit y
is <1NTU at all times. W here a risk f rom Cryptosporidium has been
identif ied in relat ion to a groundwater source and its catchm ent, then
companies should be carr ying out monit oring of the raw wat er and this
should identif y the nature of the risk and the suff iciency of the control
measures.
Table 14 illustrates t he potential groundwater Cryptosporidium risk in the
region and compares it to the actual Cryptosporidium risk in 2014. Out of a
total of 663 groundwater abstract ion points, 135 were subject ed to risk based monitor ing f or Cryptosporidium and the risk was ver if ied by positive
oocyst det ections at only thr ee abstraction points ser vin g the f ollowing
treatment works : Haslemere (T MS); Cookham ( SEW ); Pembury (SEW ).
During 2014 ther e were no turbidit y f ailur es associat ed with any of these
works.
26
London and South East region
In Januar y and Febr uar y , as part of the wider Thames Valley f looding
event, Thames W ater notif ied the Inspect orate of increasing turbidit y at the
boreholes ser ving Hambleden works near Medmenham (see Annex 3).
Retrospectively, in September, the company reported Crypt osporidium
detections f rom f our samples collected during the earlier event . Two of the
boreholes ser ving this works are located ver y close to the r iver but the
turbidit y did not exceed 1NTU. However, an audit by the Inspectorate in
2015 f ound that the UV equipment had not been in use dur ing 2014
because it was not f it f or purpose. The Inspectorate is ser ving a Notice to
require the company to addres s the Cryptosporidium risks at this site.
In Februar y, Thames W ater reported a turbidit y result of 10.7NTU in a
sample taken f rom Bedwyn treatment wor ks near Marlborough. This was
notif ied to the Inspectorate as an event ( see Annex 3). This site is not at
risk from Cryptospor idium . The f ailure was attributed to dist urbance of
chalk deposits der ived f rom the boreholes that had accumulat ed in the
pressur ised contact vessels. The Inspectorate put in place a Notice
requiring the company to clean the tanks and , if necessar y, t he chalk
boreholes. The company has since deter mined the need to install f iltration
as the permanent remedy (see Annex 4).
Also in 2014, Thames W ater had f ailures of turbidit y at t wo ot her
groundwater works: Deptf ord near Lewisham and Latton near Cirences ter.
Both were reported to the Inspect orate as events (see Annex 3). At
Lewisham sediment derived f rom a redundant part of the works (GAC) had
built up in the contact tank, which had not been cleaned out. At Latton, the
f ailure occurred when the company was carrying out f lushing as part of an
assessment of the condition of the boreholes and a cr itical valve had not
been f ully closed. Companies are rem inded that all tempor ar y or
permanent modif icat ions to a works must be done in light of a
comprehensive review of all the r isks that might arise as a consequence
both in the short ter m and in the longer term.
Southern W ater detected Cryptospor idium on two occasions in October at
Ventnor, a groundwater works on the Isle of W ight where the r isk has been
identif ied and control is by means of cont inuous monitor ing of turbidit y and
automatic shutdown. Turbidit y at the time was normal and the works was
not shut down. During the year, turbidit y failures occurred at two other at risk groundwater wor ks oper ated by the company (Ba lsdean near
Rottingdean and Mile Oak near Hove), where shut down did occur .
In 2014, South East W ater had f ive f ailur es of turbidit y at f our groundwater
works: (Ospringe, 2; Sheet, 1; Newnham, 1; W estwell, 1). At Ospringe
works, the two f ailur es were not consider ed representat ive of water
entering supply and the sampling f acilities have been moved to a more
27
Drinking water 2014
suitable location. At the remaining sit es the f ailures were attributed to
disturbance of deposits of chalk or manganese during pu mp st art up. Also
in 2014, Af f inity W ater reported a turbidi t y f ailure at its Therf ield Hea th
works near Royston that was attributed t o a corroded valve on a sample
tap that was replaced. Companies are reminded of the need t o pay greater
attention to sampling practice to ensur e all samples are representative of
the qualit y of water being supplied to consumers.
In March, South East W ater completed a scheme to install ultr aviolet (UV)
treatment f or the inactivat ion of Cryptosporidium at Fr iston works, near
Eastbourne. This scheme will improve the saf ety of water supplied to
37,000 consum ers.
During AMP6, sever al companies in the London and South East region
have comm itted to install addit ional treat ment to minim ise the risk of
Cryptosporidium : Portsmouth W ater (Eastergate and W estergate by 2016);
Thames W ater ( Haselmere by 2016); During 2014 the Cryptosporidium
monitor ing at these sites gave sat isf actory results.
Table 14: Crypt osporidium risk assessment and monitori ng of
groundw ater abstraction points in London and South East region in
2014
Numb e r of
ab st r a ct i on
point s
Numb e r of
ab str a cti on poi nts
w her e raw w at er
is mo nito r ed fo r
Cr ypt osp or id ium
Numb e r of ab st ra ct io n
point s w h er e r is k of
Cr ypt osp or id ium w as
v er ifi ed * b y th e
det ect ion of oo c yst s
21 2
4
0
P orts m ou th W ater
19
0
0
S ut to n a nd E as t
S urre y W ater
57
0
0
S ou th E as t W ater
12 6
79
2
S ou th er n W ater
12 3
48
0
T ham es W ater
12 6
4
1
Reg ion tot al
66 3
13 5
3
1, 9 61
20 8
27
Comp an y
Af f in i t y W ater
Indu st r y tot a l
*verified means either positive detection of Cryptosporidium oocysts or data quality insufficient.
Unclear data is assumed to be positive.
Surface w ater w orks
Turbidit y in surf ace water is related to sediment and biological matter.
Following rainf all the f low and hence the t urbidit y in rivers and strea ms
28
London and South East region
can rise ver y quic kly and values in excess of 100 NTU are not uncommon.
Surf ace water may be abstracted into reservoirs wher e storage of the
water allows particles to settle out; however, some of these reser voirs do
not have a suff iciently long retent ion t ime f or settlement of pathogens such
as Cryptospor idium . All surf ace waters are likely to cont ain some f aecal
matter originat ing f rom animals, birds and sewage works discharges. For
this reason, surf ace water must be prepared f or disinf ection (clar if icat ion
and f iltration). The Bouchier report recommended continuous turbidit y
monitor ing af ter f iltration at surf ace water works against a perf ormance
target f or each individual f ilter of <1NTU. Since turbidit y can interf ere with
the eff iciency of disinf ection , it is a crit ical control measure t hat should be
validated by continuous on - line monitor ing of f iltered water with alarms set
to ensure that action is taken to ensure t hat turbidit y in water entering the
f inal disinf ection stage is <1NTU at all times. W he re a risk f rom
Cryptosporidium has been identif ied in the catchment upstream of the
abstraction point, then companies should be carr ying out monitor ing of the
raw wat er and this should i dent if y the nature of the risk and the suf f iciency
of the control meas ures.
Table 15 illustrates t he potential surf ace water Cryptospor idium risk in the
region and compares it to the actual Cryptosporidium risk in 2014. Out of a
total of 62 surf ace water abstract ion points, 45 were subjected to risk based monitor ing f or Cryptosporidium and the risk was ver if ied by positive
oocysts detections at more than half (27) of these abstraction points
ser ving 26 works . During 2014 there was a turbidit y f ailure at just one of
these sites ( Barcombe Mills SEW ) .
A value of 4NTU was recorded in a sample collected in July f rom South
East W ater’s Barcombe Mills No.1 works, near Lewes, East Sussex. Ear lier
in the year dur ing the wider f looding event the company reported f ive
positive samples f or Cryptosporidium oocysts, ver if ying the risk.
Permanent mitigation of the risk by means of newly installed UV
disinf ection was commissioned in Januar y benef iting 220,000 consumers
supplied with water f rom Barcombe Mills works. Following the turbidit y
f ailure in July, which the company attr ibuted to sedime nt, the contact tank
was cleaned out.
In March 2014, the company complet ed t he installat ion of UV disinf ection
at Arlington treatment works, near Eastbourne, where Cryptosporidium
oocysts were det ect ed in Februar y. This has impr oved the saf ety of this
supply, which ser ves 90,000 consumers in Folkington and Heathf ield
zones. Also in March , South East W ater completed schemes to install UV
treatment at t wo wor ks inf luenced by surf ace wat er : Greywell, near
Basingstoke, and Cr owhur st Bridge , near Royal Tunbr idge W ells. These
schemes will improve the saf ety of water supplied to 160,000 consumers.
29
Drinking water 2014
Table 15: Crypt osporidium risk assessment and monitori ng of surface
w ater abstraction points in the London and South East region in 2014
Numb e r of
ab st r a ct i on
point s
Numb e r of
ab str a cti on poi nts
w her e raw w at er
is mo nito r ed fo r
Cr ypt osp or id ium
Numb e r of ab st ra ct io n
point s w h er e r is k of
Cr ypt osp or id ium w as
v er ifi ed * b y th e
det ect ion of oo c yst s
Af f in i t y W ater
4
4
0
P orts m ou th W ater
4
0
0
S ut to n a nd E as t
S urre y W at er
1
1
1
S ou th E as t W ater
10
10
5
S ou th er n W ater
18
12
5
T ham es W ater
25
18
16
Reg ion tot al
62
45
27
39 4
18 0
12 4
Comp an y
Indu st r y tot a l
*verified means either positive detection of Cryptosporidium oocysts or data quality insufficient.
Unclear data is assumed to be positive.
Coliform bacteria at service reservoirs
Testing f or colif orm bacteria gives reassurance that the quality of water
held at these strateg ic points in the distr ibution system is adequately
maintained. The national standard requir es that at least 95% of no less
than 50 sam ples collected f rom each ser vice reser voir throughout one year
are f ree f rom all colif orm bacteria. In 2014, all ser vice reser voirs (including
water towers) in the region met this standard .
Following a colif orm f ailure in D ecember at Cleeve New reser voir Cell
No.1, near Reading, Thames W ater identif ied def ects in one half of the
contact tank at the upstream Cleeve works and took this out of service
pending repairs, which were completed in Februar y 2015. Similar issues
were ident if ied in the second half of the contact tank, which will remain out
of supply unt il repair s have been completed.
Two colif orm f ailures in Februar y and July at W iddenton Park reser voir
No.2 (near High W ycombe) led the company to identif y ingress points
which have since been repaired.
Af ter a colif orm f ailure a t Bromley reser voir in Kent, in 2012, Thames
W ater carried out repairs and returned the reser voir to ser vice in March
2013. However, af ter a f urther f ailure occurred in Februar y 2014 the
30
London and South East region
company f ound an unusually high accum ulat ion of deposits inside the
reser voir. These wer e removed and f urther repairs made to the inlet main
and sampling f acilities. Since the reser voir was returned to service in July
there have been no f urther colif orm f ailures.
A sim ilar situation occurred at Chessington B Reser voir, in Surrey, where
repairs af ter a colif orm f ailure in Septem ber were inef f ective initially and
the reser voir had to be taken out of service again. The cause of the f ailure
was subsequent ly att ributed t o the sampling f acilities, which were replaced
bef ore the reser voir was returned to supply in November.
Thames W ater’s Clar emont Square reser voir, in Islington, has been out of
ser vice await ing repairs, which require t he agreement of English Heritage,
f ollowing a colif orm failure in November. Figure 16 shows the ext ensive
nature of repairs req uired to the roof .
Figure 16: Repairs t o a listed servi ce reservoir site
Thames W ater is examining options f or improving the turnover and residual
chlorine manageme nt at f ive ser vice reservoirs (Betsoms Hill B, Bishops
W ood B, Cockf osters A, Sewardstone A and W esterham Hill) where
colif orm f ailures wer e reported during the year.
31
Drinking water 2014
Additionally sampling f acilities improvements were made by Thames W ater
at f our service reser voir sites ( Betsoms Hill A, Crouch Hill A, Eltham Old
and Blackdown) in response to colif orm f ailures during 2014. In the case of
Blackdown reser voir, this was the third f ailure since 2012. Thames W ater
was cr iticised in 2013 by the Inspectorat e f or f ailing to ensure that the
sampling f acilities at all of its sites were f it f or purpose s required by the
Regulations.
Southern W ater also has a company - wide programme of improving
sampling f acilities and the need f or this was demonstrated when , dur ing
2014, colif orm f ailur es at three ser vice r eser voirs (Upper Enham,
Longridge Telscombe and Rumsf ield Road) were attributed to def ects with
these f acilit ies. An exam ple of the poor practice that the com pany
programme is addressing was that f ound at Rumsf ield Roa d reser voir, near
Broadst airs, where t he invest igation of the colif orm f ailure in Januar y
f ound the sampling tap was drawing water f rom only one of the cells and
this cell was out of supply at the time. Companies are rem inded that
samples collected when a reser voir is out of service ar e not representative
of water enter ing supply and should not theref ore be included in data
returns to the Inspectorate.
South East W ater reser voir inspect ions following colif orm f ailures dur ing
2014 at f our sites (Kippings Cro ss, Bluebell Hill , Bur wash No. 1, Broader
Lane) have so f ar revealed roof integrit y def ects at Kippings Cross and
Broader Lane and Bur wash No. 1 reser voirs. No issues were highlighted at
Bluebell Hill. Repair s to have been completed at Kippings Cr oss and
Broader Lane reser voirs and both have been returned to ser vice. Bur wash
Reser voir No.1 was inspected in Apr il 2015 and the reser voir is currently
out of supply f or repairs.
Aff init y W ater f ound colif orm bacteria in samples f rom two dif f erent cells
collect ed in July and September f rom the Haref ield reser voir site, which
also exhibited a colif orm f ailure in 2013. The company has since taken
action to improve tur nover. A colif orm f ailure occurred in Sept ember at the
company’s Salt wood reser voir , near Hythe, where a f ailure and inspect ion
in 2013 led to repair s to points of potential ingress. This will be taken into
account during the Inspector ate’s f orwar d program me of technical audit.
E.coli and Enterococci at consumers’ taps
A total of 47,384 tests f or E.coli and 3,906 tes ts f or Ent erococci were
carried out by the companies in the London and South East r egion on
samples collected f rom consumers’ taps during 2014 and ther e were eight
E.coli f ailures (1 PRT, 1 SRN, 6 TMS) and three Enter ococci f ailures
32
London and South East region
(2 TMS, 1 SEW ).There was no indication, from inf ormation gathered by the
companies, of a wider f aecal contam inat ion event in the relevant zones.
An E.coli f ailur e in September in a sample collected by Southern W ater
f rom a propert y in the Alvington zone near Cowes on the Isle of W ight was
demonstrated by the company as being due to poor tap hygiene and
appropr iate advice was given to the householder. Poor hygiene was also
proven by Portsmout h W ater when invest igating an E.coli f ailure in a
sample collected f rom a consumer ’s tap in the Sout hsea zone in June.
W ater f ittings def ects were f ound by Thames W ater during investigations
of E.coli f ailures in t hree diff erent consumer tap samples. Two were
collect ed f rom the Willesden zone (July and August) and the other in the
North Tottenham zone in August. The f aults were rectif ied and appropr iate
advice was given to the householders about maintaining good tap hygiene.
Towards the end of 2014, the company also commenced enhanced
monitor ing in these t wo zones where a higher than expect ed number of
colif orm f ailures had been reported dur ing the year. The results of this
additional monitoring have not identif ied any f urther or wider problems to
date.
In March, when E.coli wer e detected in a sample taken f rom a consumer ’s
tap in the Chipping Norton zone in O xf ordshire , Thames W ater was unable
to regain access to the premises immediately to investigate . W ritten boil
water advice was lef t f or the householder s. Two weeks later when the
company was able to gain access a minor water f ittings def ect was
identif ied. Further samples taken at the time and a week later af ter the
f aults were rect if ied all gave satisf actory results and the boil water advice
was lif ted.
Also in March, a sam ple f rom a consumer ’s tap in Calcot , in Thames
W ater’s Reading W est zone , was f ound to contain E.coli, however , on this
occasion no f ittings inspect ion was carried out and poor tap hygiene was
not proven. The f urther and wider samples in the zone all gave satisf actor y
results at the time.
W hen invest igating an E.coli f ailure in a consumer ’s tap sample collected
f rom a propert y in June in the Manor Park zone in east London , f urther
samples f rom the propert y wer e also positive f or colif orm bacteria and
E.coli although wider samples were satisf actor y . The consumer was
advised to boil the water and a f ittings inspection identif ied a number of
def ects. It was concluded that a sprinkler device f itted on to the kitchen
tap was the f ocal point f or the microbiological contamination and the
householder was advised ac cor dingly.
In June, when Enter ococci was detect ed in a consumer ’s tap sample f rom
a propert y in the Epping Forest zone it was investigated by Thames W ater .
33
Drinking water 2014
The company put in place enhanced monitoring at the upstream
Coppermills treatment works and carried out a f ittings inspection at the
propert y. Init ial boil water advice given t o the householder was lif ted af ter
satisf actor y results had been obtained f rom the f urther and wider
sampling. The outcome of this invest igation was inconclusive.
Thames W ater f ound more conclusive evidence of poor tap hygiene when
investigating an Ent erococci f ailure in a consumer ’s tap sample collected
f rom the Rotherhithe zone in September. A swab sample f rom the tap grew
colif orm bacteria and the householder explained how the f amily’s pet cat
was allowed to dr ink direct ly f rom the kitchen tap. A f ittings inspect ion also
f ound minor def ects and the householder was given advice about tap
hyg iene to prevent a recurrence.
A wider problem was ruled out by f urther sampling when Sout h East W ater
investigated an Enterococci f ailur e in a consumer ’s tap sample collected
f rom a propert y in the Hockers Lane zone, near Maidstone in December.
However, the company did not gain access to the propert y to carry out a
f ittings inspect ion and colle ct f urther samples until March 2015 when some
def ects were ident if ied which the householder was advised to remedy.
Chemical quality
The drinking water r egulations set out the minimum testing requirements
f or all chem ical and physical param eters. A f ull s ummar y of the results of
testing by each com pany, including the r esults f or indicator parameters , is
provided on the DW I website.
The f ollowing text and Table 17 set out the results f or those parameters
where there has been a f ailure to meet a European or national standard
(mandator y qualit y standards) and any ot her parameter of int erest. In
addition, at the request of local author ities, the results of testing f or
f luoride, iron, lead, manganese, nitrate, nitrit e, pesticides and radioact ivity
are given. The Inspectorate has also included instances wher e residual
chlorine results were reported at a level t hat may be consider ed
undesirable on groun ds of consumer acceptabilit y (2 mg/l).
34
London and South East region
Table 17: Chemical and physical parameters
The number of tests performed and the number of tests not meeting the standard or
specification
Total
number
of tests
Number of
tests not
meeting
the
standard
9,911
5
AFW (2), TMS (3)
9,905
4
PRT (2), SRN (2)
200μg/l
12,678
1
AFW (1)
10μg/l
2,652
1
TMS (1)
2mg/l
13,215
4
SEW (3), SRN (1)
2mg/l
47,413
4
SEW (3), SRN (1)
Fluoride
1.5mg/l
3,799
0
Iron
200μg/l
13,663
17
Lead
10μg/l
3,932
28
Manganese
50μg/l
12,922
4
SEW (3), TMS (1)
Nickel
20μg/l
3,909
5
AFW (1), ALB (1), SEW
(2), TMS (1)
Nitrate
50mg/l
9,566
2
SRN (2)
Nitrite
0.5mg/l
9,596
0
Pesticides – total
0.5μg/l
2,569
1
SRN (1)
82,147
35
Carbendazim TMS (1),
MCPA SRN (1),
Metaldehyde AFW (12),
SEW (10), SRN (3),
TMS (8)
Current
standard or
specified
1
concentration
Parameter
Additional information
Aesthetic parameters
– odour
No abnormal
change
– taste
Aluminium
Bromate
Chlorine – residual (free)
Chlorine – residual
2
(total)
3
Pesticide – individual
2
0.1μg/l
AFW (3), SEW (10),
SRN (1), TMS (3)
AFW (2), PRT (1), SES
(1), SEW (2), TMS (22)
Radioactivity
Gross alpha
Gross beta
Total indicative dose
Tritium
Turbidity (at consumers’
taps)
0.1Bq/l
4
987
1
SES (1)
1.0Bq/l
4
974
1
TMS (1)
0.1mSv/year
0
0
100Bq/l
784
0
4NTU
14,908
2
AFW (1), TMS (1)
Notes:
1
For comparison, 1mg/l is one part in a million, 1μg/l is one part in a thousand million.
2
The value of 2mg/l is a screening value set by the Inspectorate.
3
A further 4,135 tests were done for aldrin, dieldrin, heptachlor, heptachlor epoxide, all of which met the
relevant standard of 0.03µg/l.
4
These are screening values to trigger action. The standard is ‘Total Indicative Dose’.
35
Drinking water 2014
Aesthetic parameters
Aesthetic parameters : Taste and odour
Consumers expect their dr inking water t o be clear and bright in
appearance and f ree from discernible taste o r odour. In recog nit ion of this
the Regulations st ipulate national standards f or colour, odour and taste.
Companies are required to investigate the cause of any adver se result.
In 2014, a total of nine tests f rom consumers’ taps in the reg ion exhibited
a positive taste or odour. All tests in the region met the standard f or
colour.
The posit ive detect ions of taste and odour are summarised below in
relat ion to their nature and cause as determined by the invest igations
carried out by the companies. From this inf ormation it can be seen that all
of them were conf ined to a single property and did not ref lect a wider
problem in the zone.

Tastes described as Strong/Sweet/Soapy/ Metallic : 4 (2 PRT; 2 SRN):
these descriptors usually relate to samples wher e the tap wa t er is
artif icially sof tened and while this was f ound to be the case in each of
the examples recorded and investigated in the region this year, there
were def iciencies in action taken by both of the companies.

W hen an abnormal strong (dilut ion 8) taste wa s reported in a sample
collect ed by Portsmouth W ater in November f rom a propert y in Bognor
Regis, the company f ound that the original sample had been collect ed
f rom a tap in a ut ilit y room that was sof tened artif icially instead of the
mains f ed kitchen tap , which was f ound to be of satisf actory qualit y.
Companies should ensure that samplers collect repr esent ative samples
f rom a kitchen tap and are empowered to select an alternat ive propert y
f or sampling whenever circumstances indicate the need .

In August, when Port smouth W ater recorded a strong (dilut ion 5) sweet
taste in a sample collected f rom a public house in Chichester, they
conf irmed that the tap was f ed by a wat er sof tener , but in responding
the company f ailed to require remedial action by t he owner of the public
building. In a public building the company is under a dut y to r equire that
the sof tener is removed or the taps used f or f ood and drink preparat ion
are f ed direct f rom the mains.
In Januar y, when a metallic taste was detected in a sample coll ect ed by
Southern W ater from a consumer ’s prem ises in the Rownham s zone ,
the f ollow- up sample contained a high sodium value ( 127mg/l) and had
a low hardness value . A f ittings inspection conf irmed the pr esence of
two mains f ed taps, one f itted with a wat er sof tener, but the advice
given to the householder by the company did not explain , in plain
36
London and South East region
English, the pot ential health r isks of drawing water f or drinking or f ood
preparat ion f rom a sof tened supply . The same lack of adequate advice
was evident in the co mpany’s response to another sweet/soapy taste
due to a water sof tener identif ied in a sample collected f rom a
consumer ’s prem ises in W oodingdean near Brighton in October.
Companies are reminded that they are under a dut y to pr ovide clear
advice enabling co nsumers to take action to saf eguard themselves and,
in the case of public buildings, companies must require and verif y
remediation.

Solvent/polish/ hydrocarbons : 1 (T MS). These descriptors usually relate
to situat ions where there has been a spillage of cent ral heating oil,
petrol or diesel on the propert y and this has permeated throug h the
plastic water supply pipe ; the remedy is to advise the householder on
the need to replace t he aff ected pipe and to saf eguard against f uture
spills.
In Januar y, a solvent / polish odour in a consumer’s tap sample collected
f rom a propert y in the Thatcham South zone was f ound by Thames
W ater to be due to a leak in a central heating oil tank. The company
replaced its communicat ion pipe with a barrier pipe and advised the
householder to replace the ser vice pipe in a sim ilar manner.

Chlorine/ Phenolic: 3 (2 AFW ; 1 TMS). This descr iptor usually relates to
situat ions where the low level of residual chlorine in the mains water is
reacting with a plum bing material; the remedy is to adv ise the
householder about t ypical causes, e.g. certain t ypes of kettle, appliance
hoses, tap washers etc.
Thames W ater did not f ind a cause f or a chlorine/paint odour (dilution
2) in a consumer ’s t ap sample collected f rom a propert y in the Hainault
zone in March. Follow- up and wider samples gave satisf actor y results
and residual chlorine levels were normal ( 0.45mg/l). Companies are
reminded that a f ittings inspect ion should be carried out whenever an
abnormal taste or odour is recorded.
A f ittings inspecti on by Aff init y W ater in response to a plast ic odour
reported in a consumer’s tap sample f rom the Stansted zone in Apr il
ruled out unapproved materials as the cause. The householder reported
that the premises was f requently unoccupied and was verbally advis ed
to run the tap bef ore use to address any stagnation problems .
Companies are reminded that written advice must be given t o
consumers f ollowing a sample f ailure.
In November , Aff init y W ater f ollowed up a ‘phenolic ’ odour in a sample
f rom a consumer’s prop ert y in Greenf ord, Middle sex wit h a f ittings
inspect ion and removed a def ective plast ic aerat or f itted to the kitchen
37
Drinking water 2014
tap. However, the company’s invest igation was not completed because
they were unable to collect another sample f rom the propert y to ver if y
that the action had been ef f ective.

Polish/Egg : 1 (TMS).
In August an unusual odour descr ibed as ‘Polish and Egg ’ (dilution
number 3) f rom a consumer’s property in Thames W ater’s Tooting zone
was not replicat ed in f urther samples , but the company did no t carry out
a f ittings inspection due to access diff iculties. As the smell of eggs
of ten arises in associat ion with stagnant water that is anaerobic it can
be an indicat ion of back f low or a cross connect ion with another water
system, theref ore, in such ci rcumstances companies should always
persist in gaining access to rule out any such risk.
Consumer contacts to w ater companies for taste and odour
W hen consumers experience a persistent taste or odour, they may contact
their water company to report the pro blem. Records of these contacts in
each zone are recor ded by water companies and passed to the
Inspectorat e annually. Figure 18 shows t he zone-by- zone contact rate per
1,000 populat ion across the London and South East region.
Figure 18: Rate of t aste and odour contacts per 1,000 people
38
London and South East region
Rates of customer contacts above the industr y average of 1.15 per 1 ,000
populat ion can be obser ved in Fig ure 18 f or a number of zones in the
London and South East region ( 1 SEW , 1 SRN and 8 T MS) wit h two zones
(Frampton Mansell and Sapperton zone and Brim psf ield zone (TMS)
exhibiting the highest contact rates of 4.88 and 4.03 per 1 ,000 populat ion.
W hile these are small zones, companies are reminded that they should st ill
be addr essing chang es in contact dat a in small zones because all
consumers, regardless of supply conf igurations , should receive the same
qualit y of water. For example, Brim psf ield zone (T MS) which is supplied by
a bulk supply f rom Severn Trent W ater, exhibited three taste and odour
contacts during the year, of which t wo were related to chlorine. This
situat ion should tr igger a discussion bet ween both companies about
residual chlor ine in t he bulk supply.
Southern W ater has two legally -binding AMP6 programmes of work agreed
with the Inspectorate, with Notices put in place in 2014, to install granular
activat ed carbon (GAC) treatment at Beauport Hastings treatment works
and Brede treatment works, both in East Sussex. Together these treatment
works supply Baldslow, Brede and Fair light zones. The GAC t reatment is
required to remove pesticides, and also to remove natur ally occurring
compounds present in the raw waters, such as geosmin and methyl isoborneol, which can impart earthy or musty tastes and odours to the
drinking water. In 2013 there were f ive reports of u nacceptable taste and
odour associated with these works. At both works the installat ion of GAC
should be completed by 2018, benef iting 110,000 people .
Aluminium
Alum inium can occur naturally in some water sources. Also, aluminium based water treatment ch emicals may be used at surf ace wat er works to
aid the process of f iltration.
In 2014, a total of 12,678 samples were t ested f or aluminium in the London
and South East region and just one exceeded the standard ( AFW ). The
eight other water companies in the London and South East r egion all
achieved 100% compliance with the aluminium standar d.
In Februar y, a consumer’s tap sample collected f rom a property in the
Ickenham/Denham zone b y Aff init y W ater contain ed 217µg/l of aluminium ,
1,020µg/l of iron and exhibi ted a turbidit y of 6 NTU. The sample was
collect ed at a time when a nearby main had been shut down causing a
reversal of f low that disturbed histor ic mains deposits in the local net work.
39
Drinking water 2014
Bromate
Bromate is a disinf ection by - product (DBP) and can be f ormed in dr inking
water if the surf ace water source cont ains bromide and ozone is used in
the treatment process. The process of chlorination may also produce
bromate, f or example, through the purchase and use of an unapproved
sodium hypochlor ite solution conta ining bromide or when chlor ine is
generated on site by electrolysis. In recent years, companies have put in
place control measur es aimed at meeting the standar d of 10μg/l.
In the London and South East region, out of a total of 2,652 tests, the
standard was exceeded on a single occasion (TMS ).
A bromate value of 14.5μg/l in a sample from Thames W ater’s W alton
works occurred at the end of September. This was notif ied to t he
Inspectorat e as an event (see Annex 3). The works had been out of supply
f or a period of sever al weeks immediately pr ior to the event. The
company’s investigat ion identif ied that problems were encountered with
the control of the main ozone pr ocess on start -up of the works . This was
recognised and th e works was taken off line again (but a f ter the sample
had been collected). The Inspectorate was critical of the company because
the on-line instruments used to monitor t he ozone process had not been
calibrat ed since 2013, and three of them were switched of f . There was a
similar event at this site in 2012 and this f urther event highlighted that the
company had not learnt from the f irst event. Following a recommendation,
the company carried out a review and updated procedures to ensure
monitor ing equipment is regular ly calibrat ed and main tained. All
subsequent samples have given satisf actory results f or bromate.
In previous years, the Inspector ate has r eported on the act ions taken
by the Environment Agency (EA) and t wo water companies (AFW , TMS) to
address the risk to drinking water f rom bromate pollution of a strategic
chalk aquif er caused by an industr ial sit e at Sandr idge, Hertf ordshir e. Both
companies have completed legally -binding programmes of work to put in
place appropr iate mitigation of the risk and enhanced monitor ing
continues. The pol lut er and the EA are yet to agree on a long - term solut ion
to remediat e the aquif er. (For f urther details see Drinking wat er 2009 ).
Chlorine
Chlorine is widely used as bleach and has a long histor y of use in
circumstances where the maintenance of good hyg iene is essential, f or
example, f ood preparation, swimming pools and water supplies . In the UK
levels of residual chlorine in tap water ar e ver y low, t ypically 0.1 – 0.5mg/l
and rarely exceeds 1.0mg/l in water drawn f rom taps in prem ises . This
40
London and South East region
compares ver y f avourably to the W orld Health Organisation ( W HO) healthrelated guide value of 5mg/l.
W ater companies ar e required to measur e residual chlor ine whenever
samples are collected f or microbiological analysis . Any abnor mal change
in the level of residual chlor ine in a particular supply must be invest igated.
The Inspectorate checks the action taken by companies in relat ion to any
chlorine result above 2mg/l at treatment works , service reser voirs or
zones. Across the region in 201 4, there were f our occasions when both
total and f ree chlor ine exceeded 2mg/l. The causes and actions taken by
the companies are described below.
In Februar y, a sample f rom Bray works (SEW ) exhibited a total chlor ine
value of 2.34mg/l wit h a f ree chlorine value of 2.23 mg/l. At the tim e, the
f inal water chlorine monitor (set point 2 mg/l) did not alarm and the
company f ailed to notice or retrospectively investigate this discrepancy.
Figure 19 illustrates the chlorine residual leaving Bray works during 2014.
Relatively small var iations ca n be discer ned by sensitive consumers and
companies ar e reminded that they should be regular ly reviewing residual
chlorine data and using this inf ormation t o inf orm operational practices
with a view to achieving a stable water qualit y.
Figure 19: Levels o f free chlorine at Bray w orks in 2014
In December , South East W ater reported a f ree chlorine result of 2.77mg/l
in water supplied f rom Sandy Cr oss No.1 service reser voir, in Heathf ield
near Eastbour ne. The total chlor ine was 2.87mg/l . The cause was a f au lt y
chlorine analyser associated with the aut omated booster chlorinat ion
system at the reser voir. The boost er chlorinat ion was switched off and the
chlorine levels quickly returned to normal.
41
Drinking water 2014
In Januar y, a sample from a consumer’s t ap in the W oo lmans W ood zone
gave a total chlor ine residual value of 2.15 mg/l (free 2.00mg/l). Southern
W ater took no action at the time and retr ospect ively advised t he
Inspectorat e that the result was anomalous. Companies are r eminded that
the residual chlor ine results f rom consumers’ taps should be subject to
contemporaneous checks against the expected value f or a zone.
In addition to invest igating any abnormal change in the level of residual
chlorine, water companies must also investigate and address any sit uation
where the le vel of residual chlorine is not acceptable to consumers.
Companies theref ore have in place protocols f or receiving, assessing and
recording contacts f rom consumers repor ting chlor ine-related tastes or
odours in tap water. Figure 20 maps the chlorine taste and odour
consumer contact rat e per 1 ,000 population f or all zones in the London
and South East region during 201 4.
Figure 20: Map illustrating rates of chlorine-related consumer
contact s to w ater companies per 1,000 population
As discussed above, the m ajorit y of consumer contacts about taste and
odour in the region during 2014 related to chlor ine. From Figur e 20 it can
be seen that consumers in the south east Cotswolds, Newbur y, Thatcham,
Bur wash (near Hast ings) and the western side of the Isle of W ight exhibit a
rate of reporting chlorine-related tastes and odours above the industr y
42
London and South East region
average of 0. 24 per 1,000 populat ion. This inf ormation will be taken into
account during the Inspector ate’s f orwar d programme of technical audit in
the region.
Fluoride
Traces of f luoride occur naturally in many water sources, particularly in
groundwaters. Consumers can obt ain specif ic inf ormation on the level of
f luoride in the drinking water supply to their home or workplace f rom their
water company. Fluoride is not remov ed by conventional water treatment.
Some companies f luoridate water supplies when required to do so by the
local public health authorit y as a protect ion against tooth decay. There ar e
currently no operational f luor idat ion schemes in the London and South
East region, and all 3,799 tests during 2014 met the regulat ory standard of
1.5mg/l. The level of natural f luor ide in water supplies in the r egion ranges
bet ween 0.02mg/l and 1.3mg/l. Please ref er to the DW I websit e
(www. dwi.def ra.gov. uk ) f or more inf ormatio n on f luoridation.
Lead
Lead in tap water t ypically ar ises in pr emises where the pipes and br ass
f ittings have not been ref urbished since t he 1970s when the use of lead in
contact with dr inking water was banned. The other reason why lead may
be f ound in tap water is t he illegal use of lead- based solder f or making
joints on copper pipes.
In addition to the ban, the standar d has been pr ogressively t ightened f rom
50µg/l in 1990 to 25 µg/l in 2004 and since the end of 2013 has stood at
10µg/l. Dur ing this time period water companies have assessed the risk of
lead being present in tap water at the point of use and where necessar y
installed additional water treatment (generally phosphate dosing or pH
correction) to minimise the propensit y of lead to leach out of pipes and
f ittings within consumers’ premises.
Since the only perm anent long -term solution to the issue of lead in tap
water is the removal of lead pipes and f ittings, water companies have been
engaged in a range of other activit ies to identif y where spec if ic act ion
plans f or lead removal are required, f or exam ple in social housing or
schools. If a lead f ailure occurs in a public building then water companies
and local aut horit ies are able to use their powers to require the owner to
remedy the problem; however, in relat ion to private pr opert y, water
companies and local authorit ies can only give advice, they cannot compel
homeowners to replace lead pipes or f ittings.
Figure 21 shows the position of the London and South East r egion in
relat ion to the indust ry as a whole. For the last t wo years, the percentage
43
Drinking water 2014
of samples containing less than 10µg/l lead was has been in alignment
with the industr y overall.
Figure 21: Percentage of tests meeting the standard of 10µg/l for lead
betw een 2001 and 201 4
In 2014, companies in the London and South East region reported 28
f ailures of the standard of 10µg/l out of a total of 3,932 tests (2 AFW , 1
PRT, 1 SES, 2 SEW , 22 TMS). All but f our of the f ailures occurred in
zones where the wat er is treated wit h phosphat e to reduc e the risk from
lead and the circumstances of the se other f our f ailures ( 1 AFW , 2 SEW , 1
TMS) are descr ibed below:

A lead value of 36.3µg/l was detected in a tap sample collect ed by
South East W ater from a public building in the East Ashf ord zone in
June. An inspect ion f ound no lead plumbing and the supply pipe was
made f rom galvanised iron . All f urther samples gave sat isf actory
results and the or iginal result remains unexplained. The Inspectorate
reminds companies of the need to rule out the use of lead so lder on
copper pipe when investigating lead f ailures.

In Februar y, a sample collected f rom a consumer’s tap in the
Char ing zone operat e d by South East W ater contained 14.1 µg/l of
lead. The investigation did not ident if y any lead pipework in t he
propert y, or any ot her cause of the f ailure. The consumer was
advised to run the tap bef ore use.

Thames W ater replaced its lead communicat ion pipe in response to
a lead value of 10.8µg/l in a consumer ’s tap sample collected from a
propert y in the Guildf ord District W est zone in June. The
householder was advised to replace their own supply pipe.
44
London and South East region

W hen a sample collected by Af f inity W ater f rom a consumer’s
propert y in St Albans in August contained 11 µg/l of lead, the
company identif ied t hat its communicat ion pipe was ma de f rom lead
and replaced it. However, despite having identif ied that there was a
shared supply pipe serving more than one propert y, the company
f ailed to ext end its sampling to verif y that the action taken had
secured satisf actor y res ults at each of the p ropert ies.
A Not ice is in place r equiring Thames W ater to continuously m onitor and
reassess the risk of lead in all of its zones. The process is aided with
digital mapping tools enabling communication pipe replacement to be
targeted at individual street le vel. Using this approach, dur ing AMP6 (2015
– 2020) the company expects to replace around 36,500 lead
communication pipes. During 2014, the company reported 22 f ailures of
the lead standard and 13 of these were in zones wher e at risk streets have
been identif ied. For example, Brent Cross exhibited t wo f ailur es (24.6 µg/l
in August and 17. 8 µ g/l) in October) and certain streets in Br ent Cross ar e
now f lagged as ‘high risk’ hotspots wher e all the communicat ion pipes will
be replaced.
Additionally, Thames W ater has ident if ied the need to install phosphate
dosing f or the f irst time at two works: Ashton Keynes works serving 41,000
consumers in and ar ound Swindon and Sheaf house works supplying 7,500
people in C hipping Campden , Gloucester shire. Bo th schemes are due to
be completed in 2016.
Nickel
Nickel may be present in coatings on modern tap f ittings. In 201 4, a total
of 3,909 tests were carried out f or nickel and all but f ive (1 AFW , 1 ALB, 2
SEW , 1 TMS) met the standar d (20 µg/l).
A value of 126µg/l f or nickel was reported in a sample f rom a consumer ’s
tap in the St Albans zone (Af f init y W ater) in August. The sam ple, which
also f ailed the lead standard, was collect ed at a time when the propert y
was unoccupied f or renovat ion . Further samples gave satisf actory res ults.
In March, a value of 492µg/l of nickel was f ound in a sample t aken f rom a
show home on a new development in Rissington, near Bourton -on-theW ater. In common with other inset companies, Albion W ater was using the
show home f or routine sampling because other properties on the
development were unoccupied. A combination of new f ittings and
inf requent use was considered to be the cause and the company has since
adopted a more repr esentat ive sampling programme in the zone, as more
propert ies have become occ upied.
45
Drinking water 2014
In September, a value of 63.9µg/l of nickel was detected in a sample taken
f rom a consumer’s tap at a propert y in Cr owbor ough in the Cottage Hill
zone. Although a f ittings inspection was carried out by South East W ater,
this was incomplete because the internal stop tap was boxed in. First draw
and f lushed sample r esults demonstrat ed that nickel was leaching f rom the
tap f itting and the householder was given advice about f lushing the tap
bef ore use. The company gave similar advice in relat ion to anot her nickel
f ailure in a sample collected in October from a consumer ’s tap in the
Cuckf ield zone, W est Sussex.
In response to a nickel f ailure (20.4µg/l) in a consumer’s tap at a propert y
in W est Hampstead in October, Thames W ater demonstrated that f lushing
reduced the level of nickel to below the analyt ical detection limit. The
consumer had recent ly installed new taps and was given appr opriate
advice in wr iting.
Nitrate and nitrite
Nitrate occurs natur ally in all source wat ers due to the decay of vegetabl e
material in soil. Nitrogenous f ertilisers used on arable f armland are a
signif icant source of nitrate in groundwat er. Rainf all washes nitrate f rom
the soil into lakes, river s and streams. Nitrate levels can be r educed by
water treatment or by blending wi th anot her low nitrate, water source.
In 2014, a total of 9,566 tests were carr ied out and all but t wo met the
standard (50mg/l).
A nitrate level of 52.3mg/l at a consumer ’s tap in the Brighton Middle Level
zone, W est Sussex in Januar y was f ound by South ern W ater to be linked
to a f ailure of the blending process. W ater is normally blended from two
works (Sompting and Shoreham) , but at the time of sampling only the
Sompting works was in use and nitrate levels were higher than normal due
to adverse weat her conditions . The company took steps to im prove the
reliabilit y of the blending arrangements . A Not ice is in place r equiring the
company to install treatment to remove nitrate at both of these works (and
at three other s: Burpham, Findon and Gore ) by 2016. The company is also
planning to abandon Chilbo lton works near Andover due to high nitrate.
Collectively a ll of these AMP6 schemes will benef it 340,000 consumers.
In Februar y, Southern W ater’s investigation of a high nitrate value of
66mg/l in a sample f rom a consumer ’s tap in the Nurstead zone was
inconclusive. The company not if ied the situation to the Inspectorate as an
event (see Annex 3) and concluded that the result was not representat ive
of water enter ing supply; however, this was not supported with
contemporaneous inf ormation about nitrat e levels at the Fawk ham
46
London and South East region
Longf ield works or elsewhere within the zone. Histor ic results and those
obtained subsequent ly have been sat isf actory (around 30mg/l).
In March 2014, Af f inity W ater completed a scheme to install nitrate
removal treatment at Kings W alden works serving 6,500 consumers in the
Luton area. The company has since repor ted problems with the controlling
sof tware and expect s to remedy the situation by June 2015. All nitrate
compliance results during 2014 we re satisf actory, however there was an
event in August 2014 where nitrate exceeding the standard entered supply
(see Annex 3).
Pesticides and related products
This group of substances, generically called pesticides, includes many
organic chemicals rangin g from weed killers, to insecticides and
f ungicides. W ater sources may cont ain traces of pesticide residues as a
result of agricultur al use (pest control on crops) and non -agricultural use
(herbicides f or weed control on highways, railways etc.). W ater com panies
are required to assess the risk to drinking water supplies of pesticide use
in source water catchments and then test f or those that might be present.
Companies have taken raw water monitor ing into account when
document ing potent ial and actual pesticide hazards through t hei r
Regulation 27 risk assessments . W hen pesticides are f irst detected, water
companies will enhance the monitor ing of raw water and not ify the EA to
f acilit ate appr opriate action in the catchm ent to saf eguard drinking water
qualit y.
Table 22 illustrates t he potential pesticide risk in the region and compares
it to the actual pesticide risk in 201 4. Out of a total of 725 raw water
monitor ing points, 536 were subjected to risk -based monitor ing f or
pesticides and the risk was ver if ied by posit ive detection of pesticides at
391 abstraction points.
47
Drinking water 2014
Table 22: Raw w ater monitoring point s at risk from pestici des in 201 4
Numb e r of
raw w at er
monit o ring
point s
21 6
Raw w ate r
monit o ring po int s
monit o red fo r
pe sti ci de ri sk
18 4
Numb e r of r aw w ate r
monit o ring po int s
w her e p e sti ci de ri sk
v er ifi ed b y m oni to rin g
17 2
P orts m ou th W ater
23
21
17
S ut to n a nd E as t
S urre y W ater
58
13
12
S ou th E as t W ater
13 6
93
63
S ou th er n W ater
14 1
10 2
34
T ham es W ater
15 1
12 3
93
Reg ion a l tot a l
72 5
53 6
39 1
Indu st r y tot a l
2, 3 58
1, 4 95
1, 0 58
Comp an y
Af f in i t y W ater
Data are for raw water monitoring points in the region in 201 4. Verification of risk is based on
a t l e a s t o n e s a m p l e c o n t a i n i n g p e s t i c i d e a b o v e t h e l i m i t o f d e t e c t i o n . A l b i o n W at e r ,
I n d e p e n d e n t W a t e r N e t wo r k s a n d S S E W a t e r d o n o t o p e r a t e a b s t r a c t i o n p o i n t s i n t h e r e g i o n .
The outcome of pesticide risk management by companies in t he region was
that there wer e 35 f ailures of the individual pesticide standard in 201 4,
and one f ailur e of the total pesticide s standard. The circumstances and
substances involved are summarised below.
Carbendazim
Carbendazim is a f ungicide used f or the control of disease in a range of
agricult ural cr ops and turf . The standard is 0.1 µg/l.
In September, when carbendazim was dete cted at a level of 0.26μg/l in a
sample of treated water at Thames W ater’s Coppermills works, samples
f rom the raw water impounding reser voir and abstraction points taken at
the same time conf irmed the presence of carbendazim but at levels below
0.1µg/l. Carbendazim was not detected in samples of treated water in the
downstream distribution net work. Copper mills works has GAC in place,
which should remove carbendazim. Companies are rem inded of the need to
actively manage abstraction and treatment making adju stments whenever
there is new evidence about the range of substances and concentrations
present ing in the raw water.
MCPA
MCPA is a her bicide f requently f ound with other herbicides. It is mainly
used f or weed control in lawns, amenit y agriculture and c er eals. The
standard is 0.1μg/l.
48
London and South East region
In April, MCPA was detected at a level of 0.103μg/l in a sam ple f rom
Southern W ater’s Test wood works near Southampton. There have been no
previous or subsequent f ailures at this works and there is no GAC
treatment in place , which is ef f ective at removing MCPA. Dur ing 2014 the
company entered int o a legally - binding agreement to assess t he pest icide
risk in the catchment and work wit h EA in relat ion to the saf eguard act ion
plan f or the catchment.
Metaldehyde
Metaldehyde is the active ingredient in some slug pellets. The standard is
0.1µg/l. In 2014, companies in the London and South East r egion
collect ively reported 33 f ailures of the pesticide standard ( 12 AFW ,
10 SEW , 3 SRN, 8 TMS) due to metaldehyde at works across the London
and South East region. All except t wo companies (PRT and ALB) have
been carrying out catchment management invest igations throughout the
AMP5 per iod which has led to impr ovem ents in abstract ion m anagement at
high risk periods , wit h a range of the sol utions according to the specif ic
supply arrangements and f eatures. The Inspectorate has required
companies to continue developing these solutions in each of their high risk
catchments during the AMP6 period (see Inf ormation Letter 01/2014 issued
Februar y 2014).
An example of the benef it of improved abstraction managem ent can be
obser ved in the results reported by Sutton and East Surrey W ater in
relat ion to Bough Beech works that impounds water f rom the River Eden.
Since putt ing in place an enhanced monit ori ng and abstract ion regime,
along with f requent regeneration of carbon, there have been no
metaldehyde f ailures in treated water leaving Bough Beech works during
2013 and 2014. Key to this success has been the development in 2012 of
an in- house rapid analyt ical protocol (see Figure 23) and, whi le not
accredited, this method produces quick results to assist with operational
decisions.
49
Drinking water 2014
Figure 23: Anal yst review ing rapid
turn around HPLC results
Figure 24: Sampling at Bough
Beech reservoir
Thames W ater has developed a predict ive model f or managing abstraction
into its raw water im pounding reservoirs based on rainf all and other
indicators. Dur ing 2014, this regime was successf ul, with no metaldehyde
f ailures, in relation t o the reser voir complex to the west of London dr awing
water f rom the River Thames and ser ving f our of the large works supplying
London (Hampt on, Kempton Park, W alton and Ashf ord Common) . However ,
in 2014, this model was less successf ul in predicting metaldehyde in the
River Lee reser voir complex supplying water to North London via the
Coppermills works . The company is ref ining the model to take account of
the higher levels of metaldehyde (maxim um value of 0.305µg/l) seen in the
River Lee in 2014.
In December, Aff init y W ater detected metaldehyde at a concentration of
0.103μg/l at a consumer’s tap in the North Mymms zone. The raw wat er
qualit y ser ving the North Mymms treatment works is adversely impacted by
a landf ill site, theref ore the catchment management appr oach is unlikely to
be benef icial and the company is invest igating treatment options.
In October, Southern W ater detected metaldehyde at 0.726μg/l in a sample
f rom Burham works. This is the highest r esult in treated water reported by
a company in the region during 2014. Due to th e strategic nature of
Burham and the lim ited raw water storage capacit y (Eccles Lake, which
50
London and South East region
abstracts f rom the River Medway), the company is unable to stop
abstraction f or other than short time periods. A legally -binding programme
of work is in place to de velop a long -term solut ion to the situation at this
site by March 2018.
Five companies in the London and South East Region (AFW , IW N, SSE,
SEW , TMS) import water f rom neighbouring companies that is at risk of
metaldehyde. The arrangements in place f or man aging the risk in relat ion
to these supplies depends on inter -company bulk supply agreements and ,
in 2014, the Inspect orate carried out an audit of these arrangements (see
Chapt er 6: Technical audit activity ). The Inspector ate f ound out of date
bulk supply ser vice agreements were commonplace , with a lack of
document ed procedures f or communicating between companies about
water qualit y risks and monit oring. Inf ormation Letter 01/2014 reminded
companies that they cannot introduce new bulk supplies or transf ers where
the imported or transf erred water is at risk f rom metaldehyde whereas the
receiving zone is not at risk.
In September 2014, t he Inspectorate wrot e to all companies to explain the
f inal report ing requir ements 2 f or the AMP5 catchment management
schemes and the f ollow on AMP6 legally - binding program mes of work.
Radioactivity
Gross alpha/gross beta/ total indicati ve dose
Radioactivit y in raw water can occur naturally in the environment or f rom a
specif ic point source emission. W ater companies are requi r ed to screen f or
radionuclides that emit either alpha or beta particles. If such screening
exceeds guide values ( gross alpha 0.1Bq /l, gross beta 1.0Bq/l) then f uller
analysis f or specif ic radionuclides is carried out to determ ine t he origin.
Under these c ircumstances the t otal indicative dose (TID) must be
calculated. TID is a measure of the eff ective dose of radiat ion through
consumpt ion of the water and no f urther action is required if the guide
value of 0.1mSv/ year is not exceeded .
W here screening and other inf ormation has shown there to be no risk
relat ing to radioact ivit y in a specif ic wat er supply, companies can apply
f or, and have been granted, an exemption f rom f urther radioactivit y
monitor ing (known as a waiver) by the Inspectorate (see Tr itium section).
For TID, in the London and South East r egion, a waiver has been granted
f or 103 out of a total of 521 zones. Companies with waivers f or some or all
2
h t t p : / / d w i . d e f r a . g o v. u k / s t a k e h o l d e r s / i m p r o ve m e n t - p r o g r a m m e s / c a t c h m e n t -
undertakings.pdf
51
Drinking water 2014
of their zones are Aff inity W ater (76 zones), SSE W ater (8 zones) and
Sutton and East Surr ey W ater ( 19 zones). In 2014, SSE W ater renewed
expired waivers on t wo zones and sought a new waiver cover ing New
South Quarter, and Southern W ater were granted a waiver covering 90
sites. Thames W ater have submitted inf ormation to support an application
f or a TID waiver covering 69 works.
In 2014, the companies in the London and South East region carried out
1,961 radioactivit y screening tests and, t here wer e just t wo samples that
exceeded scr eening values: 1 SES (gross alpha) and 1 TMS ( gross beta).
A gross alpha screening value of 0.128 Bq/l was reported by Sutton and
East Surrey in a sam ple f rom its W estwood groundwat er works serving the
Kent Hatch zone in June. This works has a histor y of occasional f ailures of
the screening level of 0.1Bq/l and in August the company provided the
Inspectorat e with a report to demonstrat e that the TID is not likely to
exceed the guide value of 0.1mSv per year. Af ter consultation with Public
Health England ( PHE), the Inspector ate has raised some concerns with the
company about the sampling and analytical techniques employed and
f urther work may be required.
In Januar y, Thames W ater detected a gross beta result of 1.82Bq/l at
Farmoor works which supplies large part s of Oxf ordshire, and Swindon. All
f ollow- up samples, including raw wa ter and within -treatment process , were
satisf actor y and the EA has conf irmed that there are no contr olled nuclear
f acilit ies upstream of the River Thames abstraction points. This result was
concluded as anomalous and not likely to recur.
Tritium
Monitor ing f or tritium is necessar y only where a source of tritium is present
within the catchment and it cannot be shown on the basis of other
sur veillance program mes or investigations that the level of tritium is well
below its parametr ic indicator value of 100B q/l.
In 2014, a total of 784 tests f or tritium were carried out in the London and
South East region by six companies (4 ALB, 12 IW N, 114 PRT, 430 SEW ,
211 SRN, 13 SSE) and all of the results were below the scr eening value of
100Bq/l.
In the London and Sou th East region a waiver has been granted f or tritium
f or 103 zones f rom a total of 521. Companies with waivers f or some or all
of their zones are Aff inity W ater (76 zones), SSE W ater (8 zones) and
Sutton and East Surr ey W ater (20 zones). In 2014, SSE W ater renewed
expired waivers on t wo zones and sought a new waiver cover ing New
South Quarter, Thames W ater submitted inf ormation to suppor t an
52
London and South East region
application f or a TID waiver cover ing all of their works and Southern W ater
were granted a waiver cover ing 90 sites.
Monitor ing waivers t ime expir e af ter f ive years and the Inspectorate has
been in discussion with companies dur ing 201 4 to ensure they are now
carrying out monitoring in those situat ions where a waiver had not been
renewed.
Inf ormation Letter 06/2013 advise d com panies about the new EU Direct ive
made under the Eur atom Treaty concerning the requirements f or
radioact ivit y monitor ing of drinking water. These requirements must be
implemented in national legislat ion by 28 November 2015. Dur ing 2014 ,
the Inspector ate has been working closely with Def ra to ensur e the
necessar y changes are made to the dr inking water regulations. The
principal change relates to the introduct ion of a monitoring standard f or
radon because the other requirements ar e already in place. The
Inspectorat e, on behalf of Def ra , will be consulting the industr y on the
proposed changes to the Regulations over the summer of 2015.
Maintaining water quality in distribution
Elevated levels of iron or manganese ar e objectionable to consumers
because t he water may appear turbid or discoloured due to unsightly
deposits and may also stain laundr y and water f ittings. Since 2004 the
Inspectorat e has been monitor ing the progress of companies’ distr ibut ion
maintenance work, using an index made up of three par ameters (turbidit y,
iron and manganese). Figure 25 shows t he improvement over time in the
London and South East region with the f igure standing at 99.94% f or the
last t wo years .
53
Drinking water 2014
Figure 25: Percentage of tests meeting the standards for t urbidit y,
iron and manganese
N o t e : I W N L b e g a n s u p p l y i n g wa t e r i n t h e r e g i o n i n 2 0 1 0 . A l l o f t h e i r t e s t s m e t t he s t a n d a r d s f o r
turbidity, iron and manganese.
S S E W a t e r b e g a n s u p p l y i n g wa t e r i n t h e r e g i o n i n 2 0 0 8 . A l l o f t h e i r t e s t s m e t t he s t a n d a r d s f o r
turbidity, iron and m anganese.
Discolourat ion of tap water of ten prompts consumers to contact their wat er
company. The number of people contact ing water companies about
discoloured water is reported annually to the Inspector ate in accordance
with Inf ormation Letter 1/2006. Loo king at the trend since 2008, it can be
seen f rom Figure 26 that across the industry, the numbers of consumers
contact ing their water company to complain about discoloured water has
re-established the downward trend seen bet ween 2008 and 2012. The total
f or the industr y in 2014 was 47,986. In the London and South East region,
there was an increase in contacts with the f igure now st anding at 6,131 up
f rom 5,658 in 2013, but still lower than t he 8,063 reported in 2008. O verall ,
the region accounts f or 13% of all consumer contacts f or discolouration
across England and W ales.
54
London and South East region
Figure 26: Total contacts for discolouration 2008 –2014
In 2014, the Inspect orate carried out an exercise to ident if y zones with
persistent discolouration issues and Figur e 27 illustrates the f indings. In
total, f ive zones wer e identif ied (4 SEW , 1 SRN).
The Alvington High Level zone operat ed by So uthern W ater continues to
be a cause f or consumer concern despite being the subject of an
improvement schem e to address iron (completed in J anuar y 2013).
Sim ilarly, persist ent discolourat ion contacts f rom consumers are
associated with f our South East W ater zones (Balcombe, Bur wash,
Cuckf ield, Heathf ield) not included in an improvement scheme in AMP6.
The Inspectorate expects companies to be r eviewing consumer contact
data on a continuous basis to identif y zones with persistent pr oblems that
require remediat ion, irrespective of whether the zone has been the subject
of improvement works in the past.
55
Drinking water 2014
Figure 27: Zones w ith persistentl y ele vated discolouration contacts
In 2014, across the whole of the London and South East region, out of a
total of 45,459 tests f or the f our parameters (iron, manganese, turbidit y
and benzo(a) pyrene) there were 23 f ailur es: iron 17; manganese 4;
turbidit y 2. The Inspectorate expects that companies use f ailure
investigation inf ormation to identif y risk assessments and update their
Distr ibut ion, Operation and Maintenance Strategy (DO MS). The location
and circumstances of the 2 3 f ailures in the region dur ing 2014 are
summarised below.

Aff init y W ater – iron, 3; turbidit y 1. Two of these f ailures occurred in
associat ion with an alum inium f ailur e in a sample f rom a consumer’s
tap in the Ickenham/ Denham zone (see Aluminium section). The
other iron f ailures were isol ated occurrences in diff erent zones
(Luton W est/Houghton Regis and Hillingdon/ Hayes) dealt wit h by
f lushing.

Southern W ater – iron, 1. A value of 284 µg/l of iron was f ound in a
consumer ’s tap sample collected f rom a propert y in Sandown, in the
Brading zone on the Isle of W ight. The propert y is situated at the
56
London and South East region
end of a cul-de- sac, and the f ailure was attributed to a localised
disturbance of mains deposits. The company conf irm ed that t he main
was not f lushed.

South East W ater – iron, 10; manganese 3. Two of the manganese
f ailures were in Pet ersf ield in the Tilm ore zone. This zone receives
water f rom Sheet works where there is a risk from manganese in the
raw wat er and an addit ional stage of treatment by oxidation was
installed to address the situation. The third manganese f ailur e
(93.4µg/l) was in Dur gates (Best Beech zone). The sample was
taken from a property in a cul -de-sac, and the company concluded
that the f ailure was caused by disturbance of deposits in the main,
which was subsequently f lushed.

Thames W ater – iron, 3; manganese, 1; turbidit y, 1. A consumer’s
tap sample collected from a property in Reading in March cont ained
750.9µg/l iron and exhibited a turbidit y of 10.3 NTU. On invest igation
it was f ound that the sample had been collected at a t ime whe n work
was being undertaken on a pressure reduction valve in the ar ea.
There was one consumer complaint of aerated water associat ed with
this f ailure. The other two iron f ailures in the Dagnall zone, and in
High W ycombe (W ycombe South, North and Central zo ne), were
isolated occurrences dealt with by f lushing, as was the manganese
f ailure in the Thatcham South zone.
Southern W ater has a legally- binding programme of work in place to
address discolourat ion in Chat ham (W oolmans W ood zone). The f irst
completed phase of this program me involved the replacement of 26km of
unlined cast iron mains and the lining of a f urther 57km. In 2014 , the
Inspectorat e conf irmed the scope of the second phase of wor k which will
involve replacing a further 31km of cast iron mains b y Novem ber 2018.
Aff init y W ater’s legally-binding programmes of work to address manganese
in zones ser ved by t wo of its works (Blackf ord supplying
Ickenham/Denham zone and Roydon which supplies Har low and
Epping/Ongar zones) have been delayed. The company was required to
clean mains f ed by t hese works, and in each case this had not been done
(See Chapter 6: Technical audit act ivity and Annex 4. 1 f or more detail ).
South East W ater had a legally- binding programme of work to replace
91km of mains in the Ashf or d area (Bewl and W est Ashf ord zones). The
company applied to t he Inspectorate to change aspects of th e planned
work, result ing in a r evised programme to replace 23km of main in Ashf ord
and install treatment to sequester iron at Kingsnorth reser voir when wa ter
f rom Bewl Bridge works is transf erred into the system . This work has been
completed.
57
Drinking water 2014
Chapter 5: Drinking water quality events
Chapt er 5:

Explains how events are classif ied.

Provides summary f igures of the number and t ype of events.

Illustrates industr y- wide lear ning points f rom case studies.
W ater qualit y events are classif ied into f ive broad categories based on the
initial company repor t. The categories are:
Not significant: no f urther inf ormation required by an inspect or to assess
the event.
Minor: it is unlikely t hat f urther inf ormation would be requir ed by an
inspector to assess t he event .
Significant: a f ull company report is usually required to enable an
inspector to assess t he event .
Serious: in addition to a f ull company report, the assessment may involve
more than one inspector and site visits in the investigation.
Major: in addit ion to a f ull company r eport, will require an investigation led
by senior inspectors involving extensive inf ormation gathering and usually
site visits.
In 2014, companies in the London and South East region not if ied the
Inspectorat e of 149 events. Table 28 shows how t hese events were
classif ied.
Table 28: Water qualit y e vents in the region in 2014
Nat ur e of ev e nt
A ir i n wa t er
Ch em ic a l
Dis c o l our e d wa t er
In a de q ua te t r e atm en t
Los s of s u p pl i es / p o or pr es s ur e
M ic ro b i ol o g ic a l
T as te /O d o ur
He a lt h c o nc e r n
P ub l ic c o nc er n
O th er
Reg ion ov er al l
Eng l and an d W al e s
Ri sk as s es sm ent cat ego r y ( DW I)
M inor*
Si gnif i ca nt
S er i ou s * *
20 1 3
20 1 4
20 1 3
20 1 4
20 1 3
20 1 4
3
1
3
6
3
6
1
2
3
8
7
1
6
8
11
22
12
6
10
12
3
10
1
10
3
5
2
1
3
6
3
1
16
35
5
6
1
2
5
4
2
53
90
53
53
6
22 5
28 1
19 9
21 8
3
12
* Mi n o r c a t e g o r y n u m b e r s i n c l u d e a l l n o t s i g n i f i c a n t a n d m i n o r e ve n t s
* * S e r i o u s c a t e g o r y n u m b e r s i n c l u d e a l l s e r i o u s a n d m a j o r e ve n t s
58
London and South East region
A summar y of the nature, cause and dur ation of each event categorised as
signif icant, serious or major along wit h details of the Inspect orate ’s
f indings are set out in Annex 3. Most events were of relat ively short
duration and t he company took appropriate acti on to inf orm and saf eguard
consumers and other stakeholders. A com parison of 2013 events with
those of 2014 shows an incr ease in the r eporting of minor events and there
were f ive ser ious events, compared to none in 2013.
In 2014 ther e were six ser ious events , three of which related to the severe
winter weather and associated f looding. The event aff ecting Thames
W ater’s Hambled en works and details of the impact of f looding on Kenley
works (SES) and Egham works (AFW ) are descr ibed in this section and
Annex 3. One serious event related to microbiological contaminat ion at
Kangley Bridge works operated by Thames W ater is described in Chapt er 4
– Colif orm bacteria at works and the event concern ing disinf ection at W eir
W ood works, operat ed by Southern W ater , is descr ibed in this section and
Annex 3. The sixth serious event occurred at Streatley ser vice reser voir in
Reading involving a petrol tast e and odour (see Annex 3).
Flooding of w ater suppl y infrastructure
The beginning of 2014 was charact erised by per iods of heavy rainf all
particularly in southern England where extensive f looding occurred
impact ing on some water treatment works, notably Kenley ( SES) and
Egham (AFW ) in Sur rey.
Figure 29: Emergency flood defenc es at Kenley w orks
59
Drinking water 2014
Kenley is a groundwater works and a nor mally dr y culvert adj acent to the
site began f lowing , resulting in f looding of the site in ear ly Februar y.
Sutton and East Surr ey W ater responded quickly to protect treatment
processes and power supplies with sandba gs and f lood def ences (provided
by Nat ional Grid) and to pump away f lood water with the assistance of a
multi-agency team including the London Fire Br igade and the London
Borough of Croydon, who managed the event overall. Loss of supply f rom
this works wou ld have aff ected 5 ,000 properties.
At Egham works, f looding of the River Thames threatened the sludge
treatment plant on the site. Again a multi - agency response avoided the
loss of supplies to consumers to about 110,000 propert ies with the army
installing sandbags to protect the sludge plant. The remainder of the
assets on the site were alr eady pr otected f rom the risk of f looding due to
elevation above the f lood risk level.
Inspectors carried out public conf idence technical visits to both of these
works during the event to independent ly assess that the mitig ation
measures put in place by the companies and other agencies were
comprehensively addressing all potential risks to wat er quality. These
visits enabled the Chief Inspector to provide ministers with ind ependent
reassurance that these water supplies, which remained f ully operational
throughout the emer gency, were saf e and the companies wer e being
provided with all the wider resource s necessar y.
Despite the gener ally good response and outcome, the experien ce
highlighted that both companies had f urther work to do in order to f ully
understand and mit igate the risk of f looding at these sites. There is
lear ning f or the industry as a whole in terms of the lessons learnt f rom
these events about the readiness and thoroughness of conting ency plans
f or loss of supplies f rom all sites. In particular, all companies should have
in place detailed plans regarding the availabilit y and use of cross boundar y supplies to enable the maintenance of supplies. The Inspectorat e
expects industr y- wide lear ning to have taken place wit h all companies
having complet ed the necessar y reviews and any r esultant action plans.
Companies should be able to demonstrate that the learning exer cise was
comprehensive and embedded , and this will be taken into account dur ing
the Inspector ate’s f orward programme of technical audit.
60
London and South East region
Figure 30: Flood w aters at Egham w orks
Failure to minimise the disinfection by -product – Chlorate
Sodium hypochlor ite solution is commonly used f or disinf ection , but it
requires caref ul management to avoid the solut ion decomposing with
adverse consequences. W hen decomposition occurs the concentration of
chlorate in the solut ion rises and the available chlorine is reduced. A
typical symptom of this problem is the need to dose incr easing volumes of
sodium hypochlor ite solution to achieve the required concentr ation of f ree
residual chlor ine f or disinf ection and if this situat ion cont inues then by
adding a greater volume of solution dosed there will be a consequential
rise in the concentration of chlor ate in the treated water. Chlorate causes
oxidative damage to human blood cells and theref ore W HO has set a
relat ively strict healt h -based guide value f or drinking water of 0.7 mg/l.
The Inspectorate theref ore considers wat er is not wholesome if chlorate is
present above this level.
In July, Souther n W ater detected 0.869m g/l of chlorate in a sample
collect ed f rom its Weir W ood works. This was the third such event reported
by Sout hern W ater since 2012 and the second event at t his sit e which not
only provides water supplies to the com pany’s own customers but is also a
bulk supply to customers of South East W ater. The company carried out an
audit of the supplier of sodium hypochlorite solut ion in September f or
compliance with BS : EN 901:2013 (the Regulation 31 requirement) and
identif ied a number of def iciencies in crit ical controls such as the age of
the product, storage temperature and available chlor ine concentration.
61
Drinking water 2014
Af ter the previous events Southern W ater had taken steps to i mprove stock
solution management and control to prevent a recurrence and at W eir
W ood works, the company had decided to reinst ate a cooling system on
the bulk sodium hypochlorit e tanks . As an inter im control measure the
company had in place enhanced chlora te monitor ing, which enabled event
recognit ion and rem edial action; however, the Inspectorate was crit ical
that the permanent remedy at W eir W ood had not been recorded in the
regulator y risk assessment. This omission has since been remedied and a
Notice is in place to ensure the relevant works to prevent a r ecurrence are
progressed. Senior managers should assure themselves that they have put
in place robust audit arrangements to demonstrate that their suppliers and
operators ar e adequately controlling the r isk of f ormation of all disinf ection
by- products, not just those f or which there is a specif ied parameter and
standard set in the Regulations. The need f or such procedures was
highlighted in Inf ormation Letter 05/2011. These audit arrangements
should be inf ormed by a company policy on minimising disinf ection by products.
Lack of appropriate risk mitigation
This event relates to a groundwater works in Berkshire operat ed by
Thames W ater , with an output of up to 45Ml / d, where water is abstracted
f rom six boreholes located in the f lood plain of the River Thames. Some of
the boreholes are located in close pr oximity to the river and known to be at
risk from f looding. In early Februar y, as a consequence of the severe
weather and pr olonged rainf all, there was a wid espr ead f looding event
accompanied by unprecedented high groundwater levels and the company
notif ied the Inspect orate of the presence of E.coli, colif orms and
Cryptosporidium oocysts in a sample of treated water leaving the works.
On invest igation, the Ins pectorate identif ied f rom the company’s rout ine
compliance dat a return that other sim ilar f ailures had occurred previously
on three occasions during Januar y. The event was theref ore not of short
duration, rather it had been ongoing f or a period of sever al weeks. The
Inspectorat e required the company to retrospect ively not if y the Januar y
f ailures as an event (see Annex 3).
The works is unusual in so f ar as it has a long hist or y of UV disinf ection.
The unit was f irst installed and commissioned into use in 199 8 and it was
the only method of disinf ection at the site until 2005 , when a contact tank
was installed. Thereaf ter, disinf ection at the works was by chlorination (t he
UV plant being switched of f ). B ut prior to the f looding event, in October
2013, the company had brought the UV plant back into use, to address
known risks associated with Crypt ospor idium , not withstanding the f act that
the UV unit was old and its design was not to modern standar ds.
Unsur prisingly, it was f ound not to be capable of reliably deli ver ing the UV
62
London and South East region
dose requir ed f or disinf ection and it has since been switched off again.
The Inspectorate shall put in place a Not ice requiring the company to take
steps to addr ess the disinf ection r isks at this site. Companies are
reminded that pr ior to bri nging old plant s into use there must be a robust
evaluat ion that demonstrate s their f itness f or purpose.
The f ollowing example is included in this report because of the industr y wide learning points.
A f oul smell and taste in a village w ater suppl y
Aroun d midday on 9 May reports of f oul water began to be received f rom
residents in a village in Gloucestershir e. In total that day, there were nine
contacts, including f rom the village pub and a playgroup f or pre -school
children. By late evening, consumers had been given a boil water leaf let
and bott led water. However, the handling of the event by Severn Trent
W ater caused conf usion and anger in the communit y because people were
being given inf ormation that directly conf licted with their own obser vat ions
about the f oul taste or smell of the wat er. This loss of conf idence was not
short lived and some villagers st ill do not drink unf iltered tap water.
In the days bef ore the event, Severn Trent W ater had been receiving poor
pressure calls f rom an adjacent district metered area. On the morning of 9
May a technician had been directed to check the pressure at a hydrant and
the status of a valve f eeding the area affected by low pressure. The
technician f ound a lower than expect ed pr essure on the 180mm main
shown on the mains records as ser ving the aff ected area and a valve
shown as open on these records was in f act shut. This valve was then
opened. On investig ating f urther, the technician f ound that the company’s
mains laying contractors had commissioned a new 90mm plas tic main in
September 2013, but this was not shown on the plans although it was
supplying the properties experiencing low pressure. The technician
returned to check the pressure on the new 90mm plastic main and on
f inding it was lower t han expected, revert ed the posit ion of the valve on
the 180mm main to it s original shut position. By operating the valve on the
180mm main, a volume of stagnant water was let into the net work and the
qualit y of this water was suf f icient ly f oul when it emerged f rom taps that
consumers rejected it f or use. In total there were 38 contacts reporting the
objectionable taste or odour and a normal supply was restored af ter
f lushing and sampling three days later.
The root cause of this event was poor management of mains laying
contractors so that it took eight months (September to June), and also a
consequential water qualit y event, f or the mains recor ds to be updated.
This was not an isolated occasion of consumers being adversely impacted
by actions taken as a consequence of inaccura te records. The
63
Drinking water 2014
Inspectorat e’s assessment of two events in 2010, one in 2012 and another
in 2013, were all caused by decisions taken on the basis of erroneous
mains records. Furthermore, when pleading guilty in court to the off ence of
supplying water unf it f or consumption in 2013 the company acknowledged
that mobilisation of standing water f ollowi ng changing pressur es and f low
within a system can cause unusual tastes and odours. The Inspectorate is
unimpr essed that neither compelling evidence or recommendat ions or
prosecut ion, resulted in decisive prevent ative action to deal eff ectively
with def iciencies in t he governance of f ramework contractors. Companies
are reminded that the speed of recording changes to mains on the live
system f ollowing the commissioni ng of new mains is a crit ical water quality
control, not an inconsequential administr ative chore unworthy of the
attention of senior m anagement.
Responding to sew age like tast e and odour reports by consumers
In November , a cust omer contacted Severn Trent W ater reporting that the
tap water had a sewage like taste and odour. Localised , but serious , f aecal
contamination of tap water in t wo propert ies was conf irmed by the
presence in samples of f our indicator org anisms ( E.coli, colif orms,
Enterococci and Clostridium perfringens ) . Contemporaneous samples
collect ed upstream in the net work all gave satisf actor y results , theref ore
do not dr ink advice and bottled water was given to the occupiers of both
propert ies. A detailed investigation of the supply arrangement s revealed
that a privately owned water tank was connected to the ser vice pipe
ser ving both propert ies. This tank was f ound to be in poor condit ion
allowing ingress of faecal matter f rom sheep. Further investig ation
identif ied that a third propert y was con nected to the same ser vice pipe , but
at a point upstream of the water tank. Samples f rom this third propert y
while giving satisf actory m icrobiological r esults exhibited high results f or
turbidit y (12.2NTU), iron (2,647 µg/l) and manganese (69. 9 µg/l). The
warning advice was ext ended to this thir d propert y and a Section 75 Not ice
f or a category 5 risk was ser ved on the responsible persons.
To provide protect ion to the wider distribution system, a boundar y box was
f itted to the point of connection with the com pany’s main and, addit ionally ,
a non-return valve was f itted to the tank inlet. The sect ion of ser vice pipe
ser ving the third property was f lushed and subsequent samples verif ied
that these act ions had restored to normal the water supply to this propert y.
Following notif icat ion that remedial works to bypass the exter nal tank had
been completed, Severn Trent W ater took f urther samples f rom the two
propert ies or iginally ser ved by the tank. On this occasion, Cr yptospor idium
oocysts were det ect ed theref ore f urt her remedial work was required ,
including extensive f lushing and addit ional monitor ing. In light of the
satisf actor y results obtained at this stage PHE and the relevant local
64
London and South East region
Environmental Healt h Off icer conf irmed they wer e content f or the company
to lif t the boil water advice.
This event illustrates the importance of responding quickly and eff ectively
to a report f rom a consumer of a ‘sewage like’ odour or tast e in tap water.
Such contacts may be the f irst and only indication of a serious problem
and warrant an immediate and thor ough f ittings inspection. Sampling,
while important, should not be on the crit ical path to deciding on the need
to inspect the water supply arrangements; the nature of the consumer
report alone is suf f icient of itself to warrant an urgent f ittings inspect ion to
saf eguard public health. As this case hig hlights, sampling by itself does
not f ully ident if y either the cause or the remedy. Companies also need to
appreciate that , depending on the exact supply arrangements; any
contamination may be interm ittent making sampling an unreliable f irst line
response. The Inspectorate recommends that companies check to ensure
that protocols f or handling consumer wat er qualit y contacts specif ically
identif y sewage like taste and odour reports and em power f irst line
responders to pr iorit ise these f or inspection, as well as sampling.
Enforcement Order
In September , Bristol W ater experienced a burst main that resulted in a
loss of supplies to consumers, pot entially of a scale beyond t he resources
of the company’s own alternate supply pr ovision. W hil e the worst case
scenar io was avoided and the company’s operational capacit y proved
suff icient to restore supplies to normal, there wer e ser ious f ailings in
respect of the reporting of the event in accordanc e with the W ater Industry
(Suppliers’ Inf ormation) Direction 2012 (t he Inf ormation Direction). In
particular , there was misreport ing of the number of consumer s aff ected
which resulted in an underestimat ion of the extent and impact of the event,
these being f actors which inf luence the I nspector ate’s regulatory
response.
Following the Inspectorate’s assessment of this event, a provisional
Enf orcement Order was put in place in early December. The requirements
of such Orders are eff ective immediately f or a per iod of three months and
the purpose of this enf orcement measure is to ensure the saf ety and
secur it y of drinking water supplies. Brist ol W ater was required to review
and make improvem ents to their pr ocedures f or the management of water
qualit y or suff icien cy events, specif ically the methods of calculat ing and
reporting the scale of an event in terms of the populat ion potentially
aff ected.
Towards the end of the per iod covered by the provisional Enf orcement
Order the Inspectorate carried out an audit to esta blish if Bristol W ater had
complied with the Order. The company could not demonstrate that they
65
Drinking water 2014
had delivered the actions in a manner which provided the assurance there
would be no repetit ion of the original f ailings, theref ore, the Inspector ate
concluded that it was in the public int erest to put in place a f inal
Enf orcement Order, a breach of which is an off ence, enf orceable through
the courts. The process of putting in place a f inal Enf orcement Order
involves a f ormal per iod of consultat ion with the compa ny and engages the
processes as set out in the Inspectorate’s enf orcement policy
(http://dwi.def ra.gov.uk/about/enf orcement -pol/dwi- enf orcement.pdf ). Af ter
consider ing the com pany’s representat ions, the Inspect orate remained of
the opinion that a f inal Enf orcement Order was in the public interest and
the Order was put in place on 22 Apr il 2015 requir ing specif ied actions to
be completed by 12 June 2015.
This is the f irst time that the Inspect orate has f ound it necessary to
convert a provisional Order into a f inal Order to secure compliance. The
original errors by Br istol W ater had serious implications f ar wider than the
company and this was compounded by the inabilit y of the company to
demonstrate that it had learnt the lessons in a timely and ef f ective way.
The Inspectorate reminds all senior managers in the industr y that they are
responsible f or assuring themselves that the arrangements in place f or
secur ing compliance with Directions made by the Secretar y of State are
robust and capable of standing up to a udit scrutiny. A wide range of
stakeholders are required to respond to notif ications made under both the
Inf ormation Direction and the Secur it y and Emergency Measur es (W ater
Undertakers’) Direction , and the diligence of water companies is crit ically
important in triggering, or not, decision making and substantive resource
deployment by other s. The Inspectorate will not hesitate to take similar
action again in light of any sim ilar evidence of a breach of a Direction.
The objecti ve and purpose of Regulation 8 in the Pri vat e Water
Supplies Regulations
In Februar y, an MP wr ote to the Inspect orate on behalf of a constit uent
who was complaining about a ‘copper residue’ in her drinking water. In line
with normal practice, the Inspectorat e contacted the water comp any to f ind
out if they were awar e of the complaint and , if yes, to establish whether
the company had investigated appropr iat ely or , if no, to require the
company to investig ate. The company was able to conf irm that the
constit uent was not a customer on th eir billing records, but had previously
requested a direct connect ion to the mains supply f ree of charge. Her
request had been handled as a f irst time connection request, the quote f or
which was inf luenced by the nearest main being several miles away. W hen
handling her request the company did not recognise, and inf orm the local
author it y, that the existing supply to the propert y was a mains water supply
provided by means of a ‘f urther onward distribut ion’ arrangement across
66
London and South East region
land owned by another party (as d ef ined by Regulation 8 in the privat e
supply regulations).
The Inspectorate’s next action was to contact the local authorit y to make
them aware of the water qualit y complaint associated with the Regulat ion 8
supply. In March , the local author it y conf irmed that while they had
discussed and agreed the Regulation 8 arrangement with the water
company, they had not been able to investigate the complaint because the
complainant was not contactable and the owner of the adjacent premises
had recently passed away.
In May, the local authorit y contacted the Inspectorat e again t o report that
the matter had been progressed , not by t hem , but by the water company
who was installing a f ree connection to the mains supply. The company
was contacted again by the Inspect orate w hereupon it was explained that
other new mains wor k was being carr ied out in the supply zone to improve
resilience against insuff iciency , theref ore they could now meet the original
request f or a direct connect ion to this pr operty at no expense to the owner .
The Inspectorate pointed out that on complet ion of these works, the duties
on the local authorit y under the pr ivate water supply r egulat ions would f all
away, but the dut y to invest igate the water qualit y complaint did not f all
away, instead it transf erre d to the wat er company.
In July, the company reported that the connect ion to the property had been
made to the company’s newly laid main and a wat er f ittings inspection had
been carried out which had conf irmed there was no copper pipework inside
the proper t y. Additionally, sampling had been carried out and all the
results were sat isf actory. This inf ormation enabled the Inspectorate to
answer and close the original enquir y f rom the MP.
This case study highlights how requests f or new connections t o water
companies pr ovide an opportunit y to identif y Regulation 8 supply
situat ions. All companies should update their new connections procedures
so that staff are aware that these supplies should be recorded on the
private supply recor d and ther ef ore they should noti f y the local aut horit y
whenever such an arrangement comes to light.
W hile it is not uncom mon f or consumers to make a complaint about their
drinking water when they have exhausted all other routes f or resolving a
supply problem, as this case illustrates, ca re is required to ensure that
best endeavours to resolve a supply problem do not distract f rom the dut y
to carry out a timely investigation of any reported water qualit y concern.
Regulation 8 was int roduced int o the new private water supply regulations
in 2010 because it was known that this t ype of supply arr angement usually
lacked any prof essional oversight in its set up, maintenance and
management , causing a disproportionate and growing number of disputes
triggered by impaired qualit y or suff iciency f or w hich there was no means
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Drinking water 2014
of resolution. Typically, to supply a pr operty in this way t he owners will
have had to lay a long service pipe and connect this to another ser vice
pipe located on an adjacent prem ises. In doing so the owners may not
have paid regard at the time to ensuring that the pipe mater ials and
installat ion were bot h compatible and suitable. In this case it was f ound
retrospect ively that t here was no copper plumbing within the propert y,
theref ore, if the supply arrangement had not ceased, the l ocal authorit y
would have been under a dut y to establish if any part of the ‘onwar d
distr ibut ion ’ net work was made of copper, whether its condit ion was the
cause of a quality problem and , if so, who was responsible f or its
replacement. To enable such an in vest igation, the local authorit y would
need to trigger the duty of the water com pany to carr y out a f ittings
inspect ion at the pr imary prem ises (the customer of the water company)
and report on the nature and condition of the onward distribut ion
arrangement. The int ention of Regulat ion 8 was t wof old: in the short term
to provide a means for remedying def iciencies and preventing f uture
disputes f rom arising when the supply arr angements cease to be
ser viceable; and, in the longer term, by identif ying these su pply
arrangements to enable planning by the water company to im prove the
local supply inf rastructure over time so that all such propert ies can benef it
in the f uture f rom a secure and saf e direct connect ion to the public mains
supply. The Inspect orate expec ts water companies and local author ities to
be working jointly to put in place plans f or the eventual removal of all
Regulation 8 supplies. In this planning pr ocess, the r isk assessment and
monitor ing powers of both water companies and local author it ies, w hich
are now f ully aligned, should be used to gather evidence that can then be
used to enable any investment in improvements to the public water supply
inf rastructure necessar y to achieve the goal of making ‘onward
distr ibut ion’ obsolete.
Remediation of a Regulation 9 borehol e suppl y leading to the creation
of a new Regulation 8 suppl y – an exception to the guidance on
Regulation 8 suppli es?
This case study relat es to a private borehole on a f arm estate that also
ser ves 27 resident ial properties; some owne d by the estate , with the
remainder in private owner ship. Borehole water is pumped to two large
reser voirs that provide supplies to each of the properties by gravit y. The
standby backup supply to the reser voirs was by means of a metered
connection to the l ocal mains water supply locat ed within a f ew metres of
the reser voirs.
Monitor ing undertak en f ollowing the intr oduct ion of the new private supply
regulations identif ied that the borehole supply consist ently excee ded the
standard f or f luoride ( 1,500µg/l) with the highest value recorded as
68
London and South East region
1,600µg/l and the lowest being 1 ,540µg/l. Results exceeding the standar d
f or sodium were also recorded. The local author it y sought advice f rom
PHE, who in turn consulted the Inspectorate and it was agreed that the
local author it y should ser ve a Regulat ion 18 Not ice to requir e remediat ion
because both f luor ide and sodium are health -related standards.
As required by the Notice, the relevant person (the est ate manager)
considered the var ious options f or dealing with the sit uat ion ( treatment,
blending, mains supply) and concluded that the most cost effective and
reliable method was to f eed the reservoir s with mains water. A meeting
was held wit h the local water company about uprat ing and designing the
mains connection to the res er voirs so that it complied wit h the Fittings
Regulations. Following these works, the estate would be in compliance
with the Regulation 18 Not ice; however, due to some of the properties
being in private ownership, the arrangem ent would mean that the estate
would be ‘f urther distribut ing mains water ’ to these pr ivately owned
propert ies thereby cr eating a new Regulation 8 pr ivat e supply.
Bef ore conf irming the proposal as meeting the requirements of the
Regulation 18 Notice , the local author ity sough t advice f rom the
Inspectorat e. As set out in current guidance 3 on Regulat ion 8 supplies, the
purpose of the Regulation 8 legislation was to provide a means of dealing
with pr oblems of sufficiency or wholesom eness ar ising f rom exist ing supply
arrangements involving the onward distr ibution of mains wat er. The
intent ion behind the legislat ion was f or this t ype of indirect m ains water
supply arrangement to be ident if ied (and where necessar y remediated) and
prevented f rom being extended. The ult imate aim of the legislat i on was to
ensure that over tim e all properties ser ved by a supply of water from the
mains would become direct cust omers of a licen sed water company
thereby eliminating the risks associat ed with these hitherto unregulated
supply arrangements. This type of h istoric supply arrangement is usually
associated with a lack of clarit y regarding ownership, management and
control, and the inf rastructure is of ten unsuitable or beyond it s usef ul lif e.
The consequences of these attribut es was a growing number of protract ed
disputes bet ween neighbours with consequential qualit y and quantit y
complaints that were seemingly unresolvable by water companies and local
author ities.
In this case, the local authorit y was f aced with making a decision that
would endorse the cr eation of a new Reg ulat ion 8 private supply, contrar y
to guidance f rom the Inspectorate. However, as the purpose of the new
3
Current guidance on definition of a Regulation 8 supply was issued by the Drinking
W at e r I n s p e c t o r a t e o n 2 3 A p r i l 2 0 1 3 . A l l p r e vi o u s g u i d a n c e o n R e g u l a t i o n 8 s u p p l i e s
was superseded and should not be used.
69
Drinking water 2014
Regulation 8 supply was to deal cost eff ectively with a f ailing borehole
supply that was the subject of a Regulat ion 18 health -based Notice, and
the mains connection was one that was pre -existing, not new, the
Inspectorat e considered that the local aut horit y had a sound evidence
base f or endorsing the appr oach of creating a new Regulation 8 supply.
The Inspectorate em phasised the need to ensu re that the new Regulat ion
8 supply met all of the requirements of the Fitt ings Regulations, there was
clar it y regarding management and control, including maintenance and
costs, and restr ictions in place that meant it could not in the f uture be
ext ended to addit ional prem ises.
The Inspectorate also advised that had t here been no pr e -existing standby
mains connection in place, the local authorit y approach would have needed
to be dif f erent. The local author it y would have needed to require the water
company to pr epare detailed proposals f or the separately owned premises
to become direct customers of the water company. If it was then f ound that
all of the associated costs of these proposals could not be met by an
agreement bet ween t he parties (the estat e, the private premises owners
and the water company) then the local authorit y would be able to revoke
the original Regulation 18 Notice, replace it with an equivalent S ection 80
Notice f or lack of wholesomeness, and then commi ssion the works directly
using Section 81 powers, enabling recovery of the unf unded portion of the
costs by means of a putting a charge on t he properties.
The Inspectorate recommends that water companies and local authorit ies
put in place working procedures f or the joint working necessar y f or local
author ities to make use of their S ect ion 81 powers in the W ater Industr y
Act 91, to achieve the national water policy objective (f irst set out in the
W ater Act 1945), f or a piped mains supply to be accessible to all domest ic
premises in non -ur ban ar eas. As indicat ed in Drinking water 2014 – Private
water supplies in England – Chapt er 2: Number and nature of private water
supplies in England , the Inspector ate is working at national level with
Of wat to eliminate any perceived or actual regulator y barr i er s to improving
and regularising mains water provision in localities where local aut horit ies ’
implementat ion of the privat e water supplies regulations has provided
evidence of need.
No of f ences are currently under consider ation by the Inspectorate in
connection with any of the events that occurred in the region in 2014.
70
London and South East region
Chapter 6: Technical audit activity
Chapt er 6:

Descr ibes the audit strategy of the Inspectorate.

Summarises the outcome of audit activit y in 201 4.

Highlights learning points f or the industr y.
The Inspectorate has operated a risk -based approach to technical audit
since 2005 and no technical audit takes place without a reason .
Technical audit is the means by which the Inspector ate ver if ies whet her
companies ar e oper ating and maintain ing water supplies in a sustainable
manner that is likely to secure a saf e , clean supply of drinking water int o
the f uture. Audit act ivities tak e a number of diff erent f orms:

Assessment of inf ormation provided by water companies.

On-site inspection of comp any records, procedures and plans.

Meet ings to challeng e the veracit y of specif ic plans, procedur es or
programmes of work.
For the purposes of the report the audit activities in 201 4 are divided into
two tables. Table 31 summarises the outcomes of inspect i ons, including
consumer complaint investigations. Table 32 covers the outcomes of audits
relat ing to the enf orcing of water qualit y improvements.
Table 31: Outcomes from inspections and consumer compl aint
investigations in 201 4
Loc at i on an d
M ain fin din gs f rom a udit
re a son
Au di t fo cu s: Ab st r act ion an d t r eat m ent
S ou th E as t
B ulk t r a ns f er
Uns at is f ac t or y:
W ater a nd
agr e em ents
 A S er v ic e Le v e l A gr e e m ent was in pl ac e
S ou th er n
f ol l o wi ng a n e v e nt
reg ar d in g t h is bu lk s u pp l y , b ut t h is d id n o t
W ater
pro v i d e c ert a i nt y re g ar d in g t he ex ac t
s up p l y c o nf i gu ra t io n a t t h e t im e of th e
e ve n t.
 Lac k of vis i b i li t y of s u pp l y c o nf i g ur at i on
res u l te d in u n nec es s ar y s am pl i n g d uri n g
th e e v en t.
S S E W ater
B ulk t r a ns f er
G e ner a l l y s at is f ac t or y:
agr e em ent s
 S er v ic e L e v e l A gre em en ts we re in pl ac e
f or a l l b u lk s u pp l i es , b ut t h ere was a l ac k
of c lar i t y ab o ut inf orm at i on s har i n g an d
no t if ic at i ons t o DW I.
Comp an y
71
Drinking water 2014
T ham es W ater
Ut i l it i es
L im ite d
Loc at i on an d
re a son
K an g l e y Br i dg e
wor k s ; No t ic e
r eq u ir em ents
P orts m ou th
W ater
B ulk t r a ns f er
agr e em ents
T ham es W ater
B ulk t r a ns f er
agr e em ents
T ham es W ater
G o os e G r e e n
T ower E.c o li
f ai l ur e
S ou th er n
W ater
12 tr e atm en t
wor k s – b y
pas s i n g of
tur b id i t y m on i to r s
to a v o i d a lar m s
Comp an y
M ain fin din gs f rom a udit
G e ner a l l y s at is f ac t or y:
 Pr ogr es s wit h ac t io ns s et o u t i n th e N ot ic e
bro a d l y o n trac k .
 Arr an g em ents f or pr oc es s s c i en t is t tr a i ni n g
an d as s es s m en t v i e we d.
 No te d t ha t d os in g p o in ts pr ior t o t he
c on t ac t t ank s wer e s u bm erg ed in
gro u n d wat er, a tr ia l of p um pi n g ou t wa s to
be un d ert ak en im m edi at e l y.
 Ex c es s i v e d e l a y be t we en c hl or i ne dos e
an d m eas ur em en t o n t he n e w c h lo ri n e
res id u a l m on it ors . It was o uts i de of t he
c urr en t c om pa n y s ta n d ard .
 T he c om pa n y ha v e i nc l ud e d a pr oc es s f or
au t hor is at i o n of a l arm c ha n ges b y th e
W ater Q u a l it y m a na g e r a n d ar e de v e l op i n g
a s ys tem f or tr ac k in g a ll s hor t - t erm
c ha n ges t o a l arm s et t i ngs .
G e ner a l l y s at is f ac t or y:
 A gre em en t i n p lac e b u t it h a d n ot b e en
up d at e d to t h e W ater UK S er vic e L e v e l
prof orm a.
 Lac k e d i nf orm at io n a b ou t wa t er q ua l i t y
da t a. R ec om m en d ed u pd a ti n g to t h e n e w
prof orm a.
G e ner a l l y s at is f ac t or y:
 Rec om m end e d c om pa n y d e ve l ops a
proc es s t o h i gh l i gh t w ha t t he c r it er ia are
f or inf o rm in g t h e r ec e i v i ng c om p an y of
wa ter qu a l it y c h a ng es .
G e ner a l l y s at is f ac t or y:
 Com pa n y i n v es t i ga t io n h a d f o u nd a bi rd ’s
nes t ar ou n d t he s am p l e l i ne , i na d eq u at e
s ea l o n h atc h c o v er wi th f l i es i ns i d e ta nk
an d t he f l o at va l v e wa s s t uc k wh ic h m e an t
s ta g na nt wa ter c ou l d c om e i n to c o n tac t
wi t h r es e r vo ir wat er a s l e v e ls r os e an d f e ll .
 Re p ai r work s wer e i n pro gr es s .
Uns at is f ac t or y:
 Du p l ic a te s ig n at ur es o f m anag ers a n d
op er at ors i n l o g b ook s , t h er ef or e r eq u ir ed
v eh ic l e tr ac k in g d at a t o b e pro v i d ed t o
v er if y s i t e at te n d anc e.
 SC A D A a nd m on it or d at e r e qu es te d t o
v er if y a l arm s ta t us an d r ec ords .
 E v id e nc e of m anu a l a l arm o ver ri d e a nd
m is us e of m an a gers a c c es s c o de .
 T he f i n d in gs f rom th es e a ud i ts r es ul t ed in
an e ve nt in v es ti g at i o n .
72
London and South East region
Loc at i on an d
re a son
Au di t fo cu s: S a mpl e r s
P orts m ou th
T wo s am pl in g
W ater
r ou n ds
Comp an y
M ain fin din gs f rom a udit
Uns at is f ac t or y:
 G e ner a l c om pe te nc y o f t wo s am pl ers wa s
dem ons tr at e d.
 Im pro vem e nts i n t he q ua l i t y s ys tem n ot
i nc l u de d i n U K A S ac c r ed i ta t io n .
 Ne w dr af t s am pl i ng m an u a l d id n o t i nc lu d e
a ll f i e ld t es ts s uc h as c h lor i n e an d
tem per a tur e.
 P la n n ed c om pa n y a u d i t pro gr am m e of
s am pl ers is b e hi n d s c he d u le . It was n ot e d
th at ex tr a a ud i tors wer e b ei n g tr ai n ed .
 Ch l or in e d em an d o bs e rv ed at a r es er v o ir
s it e was ex pl a i ne d as be i n g du e t o a
k no wn pr ob l em wi t h a s am pl e l i ne t h at h a d
no t b ee n rec t if i ed .
S S E W ater
O n e s am pl i ng
G e ner a l l y s at is f ac t or y:
r ou n d
 Pr oc e d ur es be i n g us e d wer e t ha t of
an o th er or g an is at i o n n ot t h os e of t he
c om pan y.
 No f l us h i n g of t a p bef ore m eas ur in g
c h lor i n e r es id u a l .
 Fre qu e nc y of m ak e u p of c h lor i n e s pr a y no t
def in e d i n m an u a l.
Au di t fo cu s: Co ns um er com pl ain t h and li n g
In d ep e nd e nt
Dis c o l our a ti o n ( 1)
G e ner a l l y s at is f ac t or y:
W ater
 T he Ins p ec t or at e was c rit ic a l of t h e
Ne t work s
c om pan y f or f a i li n g t o ac t pr om pt l y af t er
i de nt if yi n g p art ic l es i n t he s up p l y .
S ou th E as t
T as te a n d od o ur
2 S at is f ac to r y.
W ater
( 2)
O th er ( 1)
1 G e ner a l l y s a tis f ac t or y:

S ou th er n
wa ter
T ham es W ater
P ar t ic u la tes ( 4)
A nim a ls i n wa t er
( 1)
Dis c o l our a ti o n ( 1)
T he Ins p ec t or at e was d is a p po i nt e d wi t h th e
l en gt h of t im e t ak en t o a d dres s t h e
c ons um er’s in i t ia l c om p la i nt ( t wo m on ths )
ho we v er proc e dur e s h a ve be e n c ha n g ed
s i nc e t o pr e v en t a r ec urr enc e.
3 S at is f ac to r y.
1 Uns a tis f ac t or y:
 T he Ins p ec t or at e was c rit ic a l of t h e
c om pan y’ s f irs t l et te r t o th e c o ns um er ,
wh ic h s ta t ed t h at res u l ts ha d b e en m ix e d
up , c a us in g t he c o ns u m er to los e
c onf id e nc e . T h e s i t ua t i on was m a de wors e
wh e n a s ec on d l et t er i nc or rec t l y s ta te d
th e ir c om pl a in t wa s a b ou t t as t e/ o do ur.
2 S at is f ac to r y.
73
Drinking water 2014
Over the last three years, the Inspectorat e has bee n pleased t o be invit ed
to attend an annual f orum f or sharing best practice with a f ocus on
prevent ing microbiological f ailures associated wit h these ser vice reser voir
assets. Each year there has been a theme f or improvement and so f ar
companies have share d inf ormation on the f ollowing: designs and locat ion
of sample taps; securit y of sites (including tree and shrub growt h that may
impact on reser voir integrity); internal inspection methodology in terms of
what to look f or, frequency of inspect ion and the u se of submersible
remotely operated vehicles f or inspect ion ; and cleaning reservoirs that are
in supply. Companies have openly shared their compliance r esults and
changes in sampling practice such as regular tap cleansing and double
disinf ection of sample points. Those attending have all report ed a year -onyear improvement in compliance since the f orum was set up. One
company, who has attended f rom the start , describes the pur pose and
benef its as f ollows: ‘ This forum has helped us as a company t o find and
share best practice ideas with ot hers, which in turn has helped to improve
our bacter iological compliance, not only at service reservoirs but also at
water treatment works ’. Another company commented ‘ We view the
conference as a valuable opportunity to shar e best pr actice, new products
and experiences as well as innovations or new ways of thinking to resolve
some of the common issues faced by water companies ’ . A thir d company
said ‘The event has evolved year -on-year to offer water companies a
premier opportu nity t o network and exchange their technical skills and
good pr actice. The support of the Inspect orate has pr ovided attendees wit h
first class feedback and has enabled each company to str ive t o improve
performance ut ilising some best pract ice in order to s afeguard the supply
of water to its customers’.
Table 32 summarises the Inspector ate’s activit y in relation to
improvements to wat er qualit y. These activities cover the putting in place
of Notices or undert akings and the checks made to ensure the work
spec if ied by the company is technically appropr iate, has been carried out
in the required timescales and the benef its to water qualit y have been
realised.
74
London and South East region
Table 32: Outcome of audit acti vities relating to enfor cing w ater
qualit y improvements
Ac t iv it y
Is s u i ng of
s ta tu t or y
i ns tr um ents
Nu mb e r of imp rov em ent p rog ra mm e s ( and out com e s)
Un d er t ak in gs :
AFW ( 3) , S EW (1), SR N ( 2), T M S ( 1) , S S E ( 1)
No t ic es :
AFW ( 2) , P RT (6 ), S E W (3), S RN ( 10) , T M S ( 8)
Re v i e wi ng
s c hem es
Sc hem es r e v i e wed :
S EW ( 10) , SR N ( 5) , T M S ( 3)
Ch a ng es of
s o lu t io n
Sc hem es ex am in ed :
S EW ( 1) , S RN (1)
Cl os ur e of
s c hem es
Sc hem es r e v i e wed f or c l os ur e:
S at is f ac tor y – AFW (1), S EW ( 12) , T M S ( 9) , SR N (1) ,
Ins p ec t i on of
s c hem es
Rec e ip t a nd r e v ie w
of r is k
as s es s m e nts
No n e du r i n g p er io d
S EW ( 1) , S RN ( 8) , P R T (2)
From Annex 4.1 it can be seen that there are a number of schemes in the
London and South East region where the ir completion dat es have not been
met.
Aff init y W ater’s scheme at Blackf ord works to address the risk associated
with manganese involves remediation of the boreholes and cleaning of the
downstream distribution system. The borehole remediat ion was completed
by the end of June 2014 as required , but the cleaning of the mains by ice
pigging is incomplet e because execut ion gave rise to water qualit y events
(see Annex 3) and work was suspended. Ice pigging has been used
successf ully elsewhere in the industr y. Similar ly, Af f init y W ater installed
manganese removal treatment at Roydon works in August 2012 as
required, but then suspended i ce pigging , theref ore the mains cleaning
work associated with this legally-binding programme of work is behind
schedule. The company is prepar ing a change applicat ion to ext end the
deadline to complete all works associated with these t wo schemes.
Thames W ater is deliver ing improvement s to the slow sand f ilter process
at Ashf ord works to meet the requirements of a Notice put in place by the
Inspectorat e in July 2012. W ork was due to be completed by t he end of
March 2015 and while the f ilter beds wer e ref urbi shed to the company’s
standards by this dat e, the associated monitor ing instruments will not be
75
Drinking water 2014
installed and integrated into the control system until June 2015. A Thames
W ater scheme at Bed wyn works has also been delayed because the
original solution to t he turbidit y problem at this site was not wholly
successf ul and the company is now considering the need to install
treatment.
For further inf ormation on the Water Supply (Water Quality) Regulations
2000, or the m icrobiological and chemical parameters cove red by the
regulations please r efer to the DWI website ( www.dwi.defra.gov.uk ).
If you have a need f or more specific information than that on our website,
please contact us on the DWI enquiry line: 0300 068 6400 .
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London and South East region
Annex 1
Further sources of information
The reports and other content are published on the DW I website only
(www. dwi.def ra.gov. uk).
The publication Dr inking water 2014 comprises the regional r eports f or
England and a report covering W ales. There are f our regional reports f or
England (Central and Ea stern, London and South East, Northern, and
W estern) and one f or W ales (in t wo lang uages). Each report presents
inf ormation f rom 2014 under the f ollowing headings:






Summar y.
W ater supply arrang ements.
Drinking water qualit y test ing.
Drinking water qua lit y results.
Drinking water qualit y events.
Technical audit activit y.
There are also separ ate reports covering private water supplies, one
cover ing England and one covering W ales (in t wo languages).
Water company look -up tables
These summarise all the r esults of water company monitor ing in 2014.
They provide inf ormation on:




what was tested;
how many tests were perf ormed;
the range of the results of testing; and
how many tests f ailed to meet the standards.
Significant drinking w ater quality events in En gland and
Wales 2014
To promote shared learning, the Inspect orate has compiled a list of all
signif icant, serious and major events that occurred in 201 4, which
illustrates the nature and cause of each event, the main actions by the
company and f indings f r om the inspector s’ assessments. Relevant content
f rom this overall list is cont ained in an annex to each regional report.
77
Drinking water 2014
Annex 2
Information relating to public water supplies published by the
Inspectorate in 2014
Information Letters
Ref
Title
01/201 4
Metaldehyde and ot her pesticides
02/2014
Regulation 28 reporting requirements
03/2014
Drinking water qualit y improvement programmes – changes to
progress reporting requirements
04/2014
Cryptosporidium monitor ing in water supplies
05/2014
List of appr oved products f or use in public water supplies in t he
United Kingdom
The letters, and their associated annexes, can be found on the Inspectorate’s website at
h t t p : / / w w w. d wi . d e f r a . g o v . u k / s t a k e h o l d e r s / i n f o r m a t i o n - l e t t e r s / i n d e x. h t m
Technical guidance

SCA The Determinat ion of Taste and Odour in Dr inking W ater
C o p i e s o f t h e a b o v e g u i d a n c e c a n b e f o u n d o n t h e I n s p e c t o r a t e ’ s we b s i t e a t
h t t p : / / w w w. d wi . d e f r a . g o v . u k / s t a k e h o l d e r s / g u i d a n c e - a n d - c o d e s - o f - p r a c t i c e /
78
London and South East region
Research
Ref
Title
DW I 70/2/249
Enhancing the value of molecular methods to the water
industr y: an E.coli case study
DW I 70/2/262
Identif ying meaningful opportunit ies f or drinking water
health risk reduct ions in the US
DW I 70/2/276
Speciat ion of manganese in dr inking wat er
DW I 70/2/283
Risks to drinking wat er f rom personal car e products and
domestic cleaning products
DW I 70/2/285
A crit ical appr aisal of existing guidance on online monitor
perf ormance data
DW I 70/2/286
Assessing the likelihood of selected veterinar y medicines
reaching drinking wa ter
DW I 70/2/287
Brass f ittings – A source of lead in dr inking water
DW I 70/2/295
Toxicological evaluation f or pharmaceut icals in dr inking
water
C o p i e s o f r e s e a r c h r e p o r t s a n d e x e c u t i v e s u m m a r i e s c a n b e f o u n d o n t h e I n s p e c t o r a t e ’ s we b s i t e
at http:// www.dwi.defra.gov.uk/research/completed -research/2000todate.htm
79
Drinking water 2014
Annex 3
Not significant and minor drinking water quality events
Nature
Number of not significant and minor events
SES (1)
Area affected (estimate of population affected)
Reigate, Surrey (8,963)
Air in water
S EW ( 1 )
East Grinstead, W est Sussex (13,573)
SRN (1)
Sittingbourne, Kent (11,150)
IW N ( 1 )
P a r t o f s o u t h we s t L o n d o n ( 6 , 6 6 0 )
PRT (1)
Bedhampton, Hampshire (1)
S EW ( 1 )
Eastbourne, East Sussex (3)
SSE (1)
C r o yd o n , D e p t f o r d a n d G r e e n w i c h ( 3 , 8 6 8 )
T MS ( 2 )
SRN (1)
Ma r l b o r o u g h , W i l t s h i r e ( 3 )
Ma r l b o r o u g h , W i l t s h i r e ( 3 , 3 0 0 )
Falmer, East Sussex (375)
N e wp o r t , I s l e o f W i g h t (4 1 5 )
C o we s , I s l e o f W i g h t ( 8 , 6 0 3 )
Parts of London (200,000)
B e xl e y, K e n t ( 3 )
C r a wl e y, W e s t S u s s e x ( 3 )
T MS ( 1 )
S wi n d o n a n d s u r r o u n d i n g a r e a , W i l t s h i r e ( 2 5 , 0 0 0 )
Chemical
SRN (3)
Discolouration
T MS ( 2 )
Health concern
Inadequate treatment
80
London and South East region
Nature
Number of not significant and minor events
A FW ( 1 )
Area affected (estimate of population affected)
E d g wa r e , N o r t h L o n d o n ( 9 , 5 0 0 )
PRT (2)
SES (1)
H a yl i n g I s l a n d , H a m p s h i r e ( 3 5 )
Catherington, Hampshire (1,803)
E a r l s wo o d , S u r r e y ( 1 6 3 )
S EW ( 1 )
Canterbury, Kent (14,000)
SRN (9)
S EW ( 1 )
S o u t h wa t e r , W e s t S u s s e x ( 1 , 2 5 0 )
W or t h i n g , W e s t S u s s e x ( 7 5 )
S a n d o wn , I s l e o f W i g h t ( 3 , 2 2 8 )
C o we s , I s l e o f W i g h t ( 8 , 6 0 3 )
S t o r r i n g t o n , W e s t S u s s ex ( 5 , 1 9 5 )
Colden Common, Hampshire (473)
I t c h e n A b b a s , W i n c h e s t er ( 2 8 )
B e d h a m a n d s u r r o u n d i n g a r e a s , we s t S u s s e x ( 2 5 0 )
Rake, W est Sussex (4,500)
P a r t s o f s o u t h we s t L o n d o n ( 1 4 5 , 0 0 0 )
Kennington, south London (78,668)
F i n c h l e y, n o r t h L o n d o n ( 5 2 , 7 3 5 )
Hainault, Essex (12,500)
E a l i n g a n d s u r r o u n d i n g a r e a s , we s t L o n d o n ( 1 8 7 , 7 5 7 )
L e wi s h a m , s o u t h e a s t L o n d o n ( 1 7 , 5 0 0 )
Kingston and surrounding areas, south west London (38,000)
B e xl e y H e a t h , s o u t h e a s t L o n d o n ( 2 0 , 0 0 0 )
A p p l e d o wn a n d s u r r o u n d i n g a r e a s ( 5 7 1 )
Southsea, Portsmouth (3)
D o wn s wo o d , K e n t ( 3 )
SSE (1)
D e p t f o r d a n d G r e e n wi c h , L o n d o n ( 4 5 0 )
T MS ( 8 )
Rotherhithe, south east London (3)
Bellingham, south east London (3)
C h i p p i n g N o r t o n , O xf o r d s h i r e ( 3 )
To t t e n h a m , n o r t h L o n d o n ( 3 )
W il l e s d e n G r e e n , n o r t h w e s t L o n d o n ( 3 )
Cirencester, Gloucestershire (3)
W es t H a m , e a s t L o n d o n ( 3 )
C l e e ve a n d t h e s u r r o u n d i n g a r e a s , B e r k s h i r e ( 3 0 0 , 0 0 0 )
Loss of supplies/
poor pressure
T MS ( 8 )
PRT (2)
Mi c r o b i o l o g i c a l
81
Drinking water 2014
Nature
Other
Number of not significant and minor events
T MS ( 1 )
Area affected (estimate of population affected)
Laboratory issues (N/A)
SRN (1)
G r a ve s e n d , K e n t ( 3 )
SES (1)
Redhill, Surrey (31,050)
S EW ( 1 )
N e wi c k , W e s t S u s s e x ( 5 1 0 )
SRN (23)
C r a wl e y, W e s t S u s s e x ( 5 )
H o ve , E a s t S u s s e x ( 2 7 5 ) o n t wo s e p a r a t e o c c a s i o n s
Southampton (68)
R yd e , I s l e o f W i g h t ( 6 9 , 3 3 8 )
Southampton (150)
Ventnor, Isle of W ight (173)
C r a wl e y, W e s t S u s s e x ( 7 5 )
R o m s e y, H a m p s h i r e ( 2 5 )
St Helens, Isle of W ight (48)
R yd e , I s l e o f W i g h t ( 7 5 )
Parkhurst, Isle of W ight (5,760)
Shanklin, Isle of W ight (1,100)
C r a wl e y, W e s t S u s s e x ( 3 )
C r a wl e y, W e s t S u s s e x ( 7 5 )
Hastings, East Sussex (1,000)
Broadstairs, Kent (18,170)
Southampton (375)
Horsham, W est Sussex (6,500)
C o we s , I s l e o f W i g h t ( 7 5 )
C r a wl e y, W e s t S u s s e x ( 4 0 0 )
Southampton (70)
Old Shoreham, W est Sussex (200)
Kings Cross, central London (3)
North Kensington, west London (3)
Enfield, north London (3)
Dollis Hill, north west London (3)
To t t e n h a m , n o r t h L o n d o n ( 3 )
Slough, Berkshire (3)
Calcot, Berkshire (3)
H a r we l l , O xf o r d s h i r e ( 3 )
W oo l wi c h , s o u t h e a s t L o n d o n ( 3 )
Mi l l wa l l , s o u t h e a s t L o n d o n ( 3 )
Public concern
T MS ( 1 0 )
82
London and South East region
Nature
Number of not significant and minor events
A FW ( 1 )
Area affected (estimate of population affected)
R i n g wo u l d , K e n t ( 3 )
Ta s t e o r o d o u r
T MS ( 2 )
Total
9 0 – AF W ( 2 ) , I W N ( 1 ) , P R T ( 5 ) , S E S ( 3 ) ,
SEW (5), SRN (38), SSE (2), TMS (34)
W oo l h a m p t o n , W e s t B e r k s h i r e ( 3 )
C h i n n o r O xf o r d s h i r e ( 3 )
1,320,068
Significant, serious and major drinking water quality events
Date and
duration
Area
07 Jan 2014
F o r 2 1 d a ys
( T MS )
Bromley by Bow,
London.
Estimate of
population
affected
250
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Ta s t e a n d o d o u r –
h yd r o c a r b o n s .
Thames Water Utilities Ltd action:

Issued a do not drink notice.

Sampled affected area.

P r o vi d e d b o t t l e d wa t e r o n r e q u e s t .

D r a i n e d a n d c l e a n e d t a n k u n t i l t h e h yd r o c a r b o n s h a d
cleared.

A d vi s e d m a n a g i n g a g e n t t o i n c r e a s e s e c u r i t y o f t h e r o o m
where the tank is housed.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
83
Drinking water 2014
Date and
duration
Area
09 Jan 2014
F o r 4 d a ys
( T MS )
Hambleden
works, near
Henley-onTh a m e s .
Estimate of
population
affected
250
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Cryptosporidium.
Thames Water Utilities Ltd action:

D e t e c t i o n o f o o c ys t s f o u n d t o b e l i n k e d t o a c h a n g e i n
t u r b i d i t y.

Notified health authorities.

S u b s e q u e n t l y a m e n d e d p r o c e d u r e s f o r n o t i f yi n g
c o m p a n i e s r e c e i vi n g a b u l k s u p p l y f r o m t h i s wo r k s .

R a i s e d t h e b o r e h o l e h e a d wo r k s .

D e ve l o p e d a p r o g r a m m e t o i n s t a l l t u r b i d i t y m e t e r s o n t h e
i n d i vi d u a l b o r e h o l e s u p p l i e s .
DWI comments and findings:

D i d n o t n o t i f y t h e e ve n t , wh i c h o c c u r r e d d u r i n g a p e r i o d
o f s e ve r e f l o o d i n g o f f l o o d i n g o n t h e R i ve r Th a m e s .

Highly critical that the company did not report January
detections of Cryptosporidium as required by the W ater
Suppliers’ Information Direction (2012) .

R e c o m m e n d e d t h a t t h e c o m p a n y r e vi e w s i t s p r o c e d u r e s
f o r t h e i d e n t i f i c a t i o n a n d n o t i f i c a t i o n o f e ve n t s a n d
e n s u r e s t h a t a l l a p p r o p r i a t e e ve n t s a r e n o t i f i e d .

H i g h l y c r i t i c a l t h a t t h e r e we r e n o t u r b i d i t y m o n i t o r s o r
o t h e r m e a s u r e s f o r i d e n t i f yi n g a d e t e r i o r a t i o n i n w a t e r
q u a l i t y a t i n d i vi d u a l b o r e h o l e s a n d r e q u i r e d t h e c o m p a n y
t o p r o vi d e a r e p o r t o n h o w i t m e e t s t h e r e c o m m e n d a t i o n s
in Badenoch and Bouchier reports .

Enforcement being progressed to address
C r yp t o s p o r i d i u m r i s k s a t t h i s s i t e .
Risk classification: Serious
84
London and South East region
Date and
duration
Area
17 Jan 2014
F o r 1 we e k
( S EW )
B a r c o m b e wo r k s ,
Tu r n e r s H i l l
C r a wl e y .
Estimate of
population
affected
3
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Cryptosporidium.
South East Water Plc action:

Sampled affected area.

B r o u g h t f o r wa r d c o m p l e t i o n o f i m p r o ve m e n t s i n c l u d i n g
installation of UV set out in a Notice already in place to
mitigate the risk of Cryptosporidium at the works.
DWI comments and findings:

S u g g e s t e d t h e c o m p a n y w o r k wi t h t h e h e a l t h a u t h o r i t i e s
t o m o n i t o r c h a n g e s i n r e p o r t e d c a s e s o f c r yp t o s p o r i d i o s i s
and giardiasis in the community to demonstrate the
b e n e f i t o f t h e i m p r o ve m e n t s .
Risk classification: Significant
27 Jan 2014
F o r 4 d a ys
( T MS )
Blackheath,
South London.
43,360
B r o wn
discolouration due
t o p l a n n e d wo r k .
Thames Water Utilities Ltd action:

Sampled affected area.

Flushed mains.
DWI comments and findings:

Th e e ve n t wa s d u e t o t h e l a c k o f a r i s k a s s e s s m e n t
b e f o r e o p e n i n g va l ve s t o i n c r e a s e d i s t r i b u t i o n p r e s s u r e i n
a zo n e k n o w n t o s u f f e r f r o m d i s c o l o u r a t i o n .

Recommended a review of the adequacy of risk
a s s e s s m e n t s wh e n u n d e r t a k i n g v a l vi n g a c t i vi t i e s a n d
consequential improvement in procedures and practices.
Risk classification: Significant
85
Drinking water 2014
Date and
duration
Area
06 Feb 2014
F o r 4 we e k s
(SES)
K e n l e y wo r k s ,
C r o yd o n .
Estimate of
population
affected
17,500
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Potential loss of
supply due to
flooding.
Sutton and East Surre y Water Plc action:

Groundwater flooding from the Caterham Bourne occurred
a f t e r a p e r i o d o f e xc e p t i o n a l r a i n f a l l .

R e zo n e d a r e a ( b r o u g h t i n wa t e r f r o m d i f f e r e n t s o u r c e ) .

Th e c o m p a n y d e p l o ye d h e a v y d u t y p u m p s a n d o ve r l a n d
p i p e s a n d wo r k e d w i t h o t h e r s t o c l o s e a m a j o r h i g h wa y
a n d u s e i t t o d i ve r t f l o o d wa t e r f r o m t h e s i t e .

Sampled affected area.

Established an emergency control room at the site .

P r o t e c t e d t h e s i t e wi t h s a n d b a g s

I m p r o ve d f l o o d d e f e n c e s .
DWI comments and findings:

R e c o m m e n d e d a c t i o n s t o i n ve s t i g a t e t h e c o n d i t i o n o f t h e
p u m p s u m p t o r e m o ve t h e u n c e r t a i n t y s u r r o u n d i n g i t s
i n t e g r i t y.

S u g g e s t e d a r e vi e w o f o t h e r s i t e s a t r i s k o f f l o o d i n g
where there are areas which cannot be supplied by
r e zo n i n g i f t h e w o r k s i s t a k e n o u t o f s u p p l y .
Recommended the company prepares robust emergency
c o n t i n g e n c y m e a s u r e s f o r s i t u a t i o n s wh e r e a s u p p l y i s
l o s t f o r a n e xt e n d e d p e r i o d .

Required details of, and timetable for, planned
i m p r o ve m e n t s i d e n t i f i e d a s n e c e s s a r y a s l e a r n i n g f r o m
t h i s e ve n t .
Risk classification: Serious
86
London and South East region
Date and
duration
Area
06 Feb 2014
For 1 day
(SRN/
Eurofins)
N/A
Estimate of
population
affected
N/A
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Eurofins
l a b o r a t o r y.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

F a i l e d t o i d e n t i f y a n d a c t u p o n a m e t a l d e h yd e f a i l u r e p r i o r
to data submission to the Inspectorate.

A u d i t o f l a b o r a t o r y i d e n t i f i e d L I MS l i m i t s f o r h i g h l i g h t i n g
m e t a l d e h yd e f a i l u r e s w e r e n o t i n p l a c e : c o r r e c t i v e a c t i o n
taken.

P u t i n p l a c e a n e l e c t r o n i c a u t o l a b e l l i n g s ys t e m .
DWI comments and findings:

U n a c c e p t a b l e d e l a y i n n o t i f yi n g I n s p e c t o r a t e d u e t o a
likely sample identification error.

S u g g e s t e d r e f r e s h e r t r a i n i n g f o r s a m p l e r s / a n a l ys t s .

Critical that the company did not identify the absence of a
failure flag against this sample before submitting its
monthly return to the Inspectora te.

R e c o m m e n d r e g u l a r r e vi e w o f b r e a c h l e ve l s o n t h e L I MS
t o p r e ve n t a r e c u r r e n c e .

N o t e d t h a t t h i s i s o n e o f a s e r i e s o f e ve n t s r e l a t e d t o
a n a l yt i c a l s e r vi c e s ( S e e D r i n k i n g w a t e r 2 0 1 3 – A n n e x 3
a n d o n e m i n o r e ve n t i n 2 0 1 4 ) .
Risk classification: Significan t
08 Feb 2014
For 24 hours
( T MS )
Hambleden
works, Henley.
26,500
Thames Water Utilities Ltd action:

Sampled affected area.

R e s p o n d e d t o i n c r e a s e d r i ve r f l o w a n d r i s i n g b o r e h o l e
t u r b i d i t y, b y r e m o vi n g t w o a t r i s k b o r e h o l e s f r o m s e r vi c e .

R e vi e w e d t u r b i d i t y a l a r m t h r e s h o l d s a n d r a i s e d t h e U V
2
dose at site from 20-40mJ/cm .

R e vi e w e d t h e C r y p t o s p o r i d i u m s a m p l i n g f i l t e r vo l u m e s a t
the site. More frequent checking is now in place.

Applied lessons learned to other sites.
Tu r b i d i t y.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
87
Drinking water 2014
Date and
duration
Area
18 Feb 2014
F o r 7 d a ys
( A FW )
E g h a m wo r k s ,
Egham, Surrey.
Estimate of
population
affected
280,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Potential loss of
supply due to
flooding.
Affinity Water Ltd action:

E s t a b l i s h e d a f l o o d m a n a g e m e n t c o m m a n d s t r u c t u r e , wi t h
clear responsibilities for different aspects of flood risk
management.

Obtained support from the army to install sandbags to
p r o t e c t t h e s l u d g e p l a n t a t E g h a m wo r k s .

P r o c u r e d b o t t l e d wa t e r a s a c o n t i n g e n c y s u p p l y .

I m p r o ve d s t o c k s o f t r e a t m e n t c h e m i c a l s a n d f u e l o n s i t e .
DWI comments and findings:

Critical that company contingency plans did not consider
the simultaneous risk of flooding at multiple sites.

R e c o m m e n d e d t h a t t h e c o m p a n y p r o vi d e a h o l i s t i c f l o o d
p l a n t h a t c o n s i d e r s a l l s i t e s a l o n g t h e R i ve r Th a m e s a n d
t h a t t h e l e a r n i n g f r o m t h i s e ve n t i s a p p l i e d t o a l l s i t e s .

Critical that the risk of flooding of the sludge plant had
not been identified in the regulatory risk assessment .

Required updating of risk assessmen ts to include further
c o n s i d e r a t i o n o f f l o o d i n g h a za r d s .
Risk classification: Serious
0 5 Ma r 2 0 1 4
F o r 5 0 d a ys
(SRN)
R yd e , I s l e O f
W ig h t .
230
Me d i a i n t e r e s t d u e
to burst main.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

Th e n e w m a i n i s t o b e d u g u p a n d r e p l a c e d .

Retrained staff.

R e vi e w o f p r o c e d u r e s .

Sampled affected area.
DWI comments and findings:

Th i s e ve n t r e l a t e d t o t h e l a yi n g o f a n e w m a i n wh i c h we n t
wrong and caused flooding.

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
88
London and South East region
Date and
duration
Area
1 3 Ma r 2 0 1 4
For 4 hours
(SRN)
S i n g l e we l l
S e r vi c e r e s e r vo i r ,
G r a ve s e n d , K e n t .
Estimate of
population
affected
66,878
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Loss of supply due
to faulty
equipment.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

Replaced faulty equipment.

Sampled affected area.
DWI comments and findings:

Th i s e ve n t wa s c a u s e d b y a f a u l t y t r a n s d u c e r l e a d i n g t o
t h e d r a i n i n g o f t h e r e s e r vo i r .

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
1 3 Ma r 2 0 1 4
F o r 6 d a ys
( T MS )
Beckenham,
South London.
10
Ma i n s b u r s t i n
p r o xi m i t y o f s e we r .
Thames Water Utilities Ltd action:

I s s u e d a b o i l wa t e r n o t i c e a s a p r e c a u t i o n d u e t o r i s k o f
c o n t a m i n a t i o n b y s u r f a c e wa t e r a n d p r o xi m i t y o f t h e
s e we r .

P r o vi d e d b o t t l e d wa t e r o n r e q u e s t .

R e p a i r e d m a i n a n d s e we r .

Sampled affected area.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
2 5 Ma r 2 0 1 4
F o r 5 d a ys
( S EW )
Petersfield.
4,688
B r o wn
discolouration due
to mains burst.
South East Water Plc action:

Repaired main.

Sampled affected area.

Flushed mains.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
89
Drinking water 2014
Date and
duration
Area
03 Apr 2014
For 1 day
(SRN)
Rochester.
Estimate of
population
affected
123
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
B r o wn
discolouration due
t o p l a n n e d wo r k .
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

Sampled affected area.

R e zo n e d a r e a ( b r o u g h t i n wa t e r f r o m d i f f e r e n t s o u r c e ) .
DWI comments and findings:

Th i s e ve n t wa s c a u s e d b y i n a d e q u a t e p l a n n i n g a n d
inaccurate records leading to the risk of discoloured
w a t e r n o t b e i n g i d e n t i f i e d a n d m a n a g e d . Th i s i n d i c a t e d
that the company had not successfully embedded
i m p r o ve d p r o c e d u r e s f o r c h e c k i n g va l ve s t a t u s a h e a d o f
p l a n n e d wo r k .

R e c o m m e n d e d t h a t f o r a l l p l a n n e d wo r k s o n t h e m a i n s
s ys t e m t h e a c t u a l va l ve s t a t u s i s c h e c k e d i m m e d i a t e l y
before the work is carried out.

Suggested that the company takes steps to ensure that all
l i n e a n d c r o s s c o n n e c t i n g va l ve s a r e r e c o r d e d a c c u r a t e l y
o n i t s g e o g r a p h i c a l i n f o r m a t i o n s ys t e m ( G I S ) s ys t e m a n d
site plans used for planned operations.
Risk classification: Significant
90
London and South East region
Date and
duration
Area
15 Apr 2014
For 6 hours
(SRN)
Saltdean Vale
near Brighton
Estimate of
population
affected
1,740
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Me d i a i n t e r e s t d u e
to mains burst.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

P r o vi d e d b o t t l e d wa t e r o n r e q u e s t .

Repaired main.

Sampled affected area.

B o t t l e d w a t e r a va i l a b i l i t y wa s o n l y s u f f i c i e n t f o r s i x h o u r s
o f p l a n n e d wo r k .

Verbal briefing of learning points to staff but procedures
not changed or updated.
DWI comments and findings:

Repeated attempts to recharge main after a planned
repair failed due to incorrect fitting ; this led to overrun of
t h e p l a n n e d wo r k s a s a c u t o u t a n d a w i d e r r e z o n i n g
e xe r c i s e w a s r e q u i r e d .

Critical that the company did not keep customers
i n f o r m e d wh e n s i t u a t i o n c h a n g e d f r o m t h e i n f o r m a t i o n
p r o vi d e d t o t h e m i n t h e 4 8 h o u r wa r n i n g n o t i c e o f t h e
p l a n n e d wo r k . Th i s l e d t o a d ve r s e p u b l i c i t y a n d l o s s o f
consumer confidence: suggested that changing the
wording of the routine warning notice would enable
c o n s u m e r s t o b e t t e r p r e p a r e f o r a c u t o f f b e i n g e xt e n d e d
for unforeseen reasons.
Risk classification: Significant
91
Drinking water 2014
Date and
duration
Area
24 Apr 2014
F o r 2 7 d a ys
( S EW )
Benenden, Kent.
Estimate of
population
affected
3
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Coliforms and
s e wa g e o d o u r d u e
to cross
c o n n e c t i o n wi t h a
r a i n wa t e r
h a r ve s t i n g s ys t e m .
South East Water Plc action:

F i ve d a ys a f t e r t h e f i r s t vi s i t t o t h e p r o p e r t y, b o t t l e d wa t e r
p r o vi d e d a n d a d vi c e g i v e n n o t t o d r i n k t h e w a t e r .

Fittings inspection identified a cross -connection to a
r a i n wa t e r h a r ve s t i n g s ys t e m a n d t h i s wa s d i s c o n n e c t e d a
week later.

A d o u b l e c h e c k va l ve wa s i n s t a l l e d a t t h e b o u n d a r y .

Sampled affected area.
DWI comments and findings:

S a m p l e s n o t a n a l ys e d f o r a p p r o p r i a t e p a r a m e t e r s .

Critical that despite the consumer reporting a sewage
o d o u r t h e f i r s t s a m p l e w a s c o l l e c t e d f i ve d a ys l a t e r .

R e c o m m e n d e d t h e c o m p a n y r e vi e w s i t s p r o c e d u r e s f o r
r e p o r t i n g r e s u l t s o u t o f n o r m a l wo r k i n g h o u r s a n d e n s u r e s
that a robust process is in place to ensure the timely
r e p o r t i n g o f a d ve r s e w a t e r q u a l i t y r e s u l t s a t a l l t i m e s .

R e c o m m e n d e d t h e c o m p a n y l e a r n s f r o m t h i s e ve n t a n d
reminds all staff of the importance of collecting
microbiological samples immediately in response to a
c o n s u m e r c o n t a c t a b o u t s e wa g e t yp e o d o u r s .



92
Risk classification: Significant
London and South East region
Date and
duration
Area
0 1 Ma y 2 0 1 4
For 3 days
( T MS )
S t r e a t l e y s e r vi c e
r e s e r vo i r ,
Reading.
Estimate of
population
affected
3,750
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Ta s t e o r o d o u r –
petrol.
Thames Water Utilities Ltd action:

P r o m p t l y i d e n t i f i e d wo r k o n a s e r vi c e r e s e r vo i r w a s t h e
cause of consumer complaints of taste/odour .

Issued a restriction of use notice .

Distributed bottled water.

Sampled affected area.

B yp a s s e d t h e s e r vi c e r e s e r vo i r .

D r a i n e d a n d c l e a n e d s e r vi c e r e s e r vo i r .
DWI comments and findings:

Critical that the EA were not informed of the discharge of
w a t e r c o n t a i n i n g s t yr e n e .

H i g h l y c r i t i c a l wi t h t h e l a c k o f c o n t r a c t o r c o n t r o l .

R e q u i r e t h e c o m p a n y t o i m p r o ve i t s m a n a g e m e n t o f
contract staff.

Poor risk assessment process .

Th e c o n t r a c t o r s w e r e n o t t r a i n e d u n d e r t h e ‘ B l u e C a r d ’
scheme.

C o n c e r n e d t h a t t h e r e s e r vo i r wa s r e t u r n e d t o s e r vi c e
wi t h o u t a d e q u a t e c h e c k s o f wa t e r q u a l i t y .

C o n s u m e r s we r e c o n f u s e d a n d wo r r i e d b y t h e l a c k o f
d e t a i l o ve r t h e a r e a s a f f e c t e d .

R e c o m m e n d e d t h e c o m p a n y r e vi e w s a n d i m p r o ve s
c o m m u n i c a t i o n t o c o n s u m e r s d u r i n g t h i s e ve n t .
Risk classification: Serious
93
Drinking water 2014
Date and
duration
Area
0 9 Ma y 2 0 1 4
For 6 hours
( T MS )
Ashford Common
works, South
W es t L o n d o n .
Estimate of
population
affected
822,452
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Disinfection
failure.
Thames Water Utilities Ltd action:

I n c r e a s e d c h l o r i n e r e s i d u a l s a t t r e a t m e n t wo r k s .

C o m p a n y c o m m i t t e d t o a r e vi e w o f f a i l s a f e s ys t e m s a t t h i s
l a r g e wo r k s .

D e t a i l e d d e s i g n o n a f a i l s a f e s ys t e m a t A s h f o r d C o m m o n
i s e xp e c t e d t o c o m m e n c e i n S e p t e m b e r 2 0 1 5 , a
p r o g r a m m e f o r a d d r e s s i n g t h i s i s s u e a t o t h e r l a r g e wo r k s
i s e xp e c t e d t o b e c a r r i e d o u t o ve r t h e A MP 6 p e r i o d .
DWI comments and findings:

R e c o m m e n d e d a d d i t i o n a l m e a s u r e s t o p r e ve n t o r r e d u c e
the likelihood of the supply of inadequately disinfected
w a t e r l e a vi n g t h i s s i t e .
Th i s i s l i n k e d t o t h e e ve n t a t K i n g s C r o s s o n 9 M a y 2 0 1 4 .
Risk classification: Significant
0 9 Ma y 2 0 1 4
For 1 day
( IW N )
Kings Cross.
1,007
Independent Water Networks action:

E ve n t a f f e c t i n g a b u l k s u p p l y w a s n o t s e p a r a t e l y n o t i f i e d
to the Inspectorate.

Appointed new staff member to address water quality
issues.

Changed notification procedures.
Bulk supply.
DWI comments and findings:

U n a c c e p t a b l e d e l a y i n n o t i f yi n g I n s p e c t o r a t e d u e t o
i n a d e q u a t e k n o wl e d g e o f s t a f f a n d p r o c e d u r e s .
Th i s i s l i n k e d t o t h e e ve n t a t A s h f o r d C o m m o n w o r k s o n 9
Ma y 2 0 1 4 .
Risk classification: Significant
94
London and South East region
Date and
duration
Area
2 9 Ma y 2 0 1 4
For 1 day
( T MS )
Fobney works,
Reading.
Estimate of
population
affected
206,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Animal ingress
into contact tank.
Thames Water Utilities Ltd action:

D i s c o ve r e d a n i m a l b o n e s d u r i n g c o n t a c t t a n k i n s p e c t i o n .

Bones identified as black-headed gulls.

I n ve s t i g a t i o n i d e n t i f i e d o p e n ve n t s i n t o t a n k a n d h i s t o r i c
e vi d e n c e t h a t a c c e s s d o o r s h a d b e e n l e f t o p e n f o r
e xt e n d e d p e r i o d s .

I n s t a l l e d t e m p o r a r y c o ve r s o n t h e a c c e s s p o i n t s a n d
s u b s e q u e n t l y d e s i g n e d a n d i n s t a l l e d p e r m a n e n t i m p r o ve d
p r o t e c t i o n t o p r e ve n t a r e p e a t o c c u r r e n c e .
DWI comments and findings:

H i g h l y c r i t i c a l t h a t n e i t h e r t h e o p e n ve n t s n o r t h e
p r e s e n c e o f g u l l s wa s t a k e n i n t o a c c o u n t wh e n t h e
c o m p a n y i n ve s t i g a t e d p r e vi o u s m i c r o b i o l o g i c a l f a i l u r e s
(first recorded in 2008).

R e c o m m e n d e d t h e c o m p a n y i m m e d i a t e l y r e vi e w s ve n t s
and hatches on all tanks to ensure all potential routes of
ingress are identified, suitable protection is in place and
t h a t a l l ve n t s a n d h a t c h e s a r e i n s p e c t e d o n a r e g u l a r
basis.

Th i s e ve n t r e ve a l e d a f a i l u r e b y t h e c o m p a n y t o l e a r n
f r o m t h e P i t s f o r d e ve n t ( A n g l i a n W a t e r ) a n d t h e D a n c e r s
E n d e ve n t ( Th a m e s W a te r ) .
Risk classification: Significant
95
Drinking water 2014
Date and
duration
Area
10 Jun 2014
For 1 day
( T MS )
Goose Green
t o we r ,
Hoddesdon,
Hertfordshire.
Estimate of
population
affected
39,772
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
E.coli.
Thames Water Utilities Ltd action:

R e m o ve d wa t e r t o w e r f r o m s u p p l y.

Sampled affected area.

R e zo n e d a r e a ( b r o u g h t i n wa t e r f r o m d i f f e r e n t s o u r c e ) .

Replaced faulty equipment.

Flushed mains.
DWI comments and findings:

S i g n i f i c a n t r e m e d i a l w o r k s we r e t a k i n g p l a c e a t t h i s s i t e
including checks on the configuration of the associated
m a i n s . DW I u n d e r t o o k a n a u d i t o f t h i s s i t e i n J u l y a n d t h e
findings are reported in the Audit Section.
Risk classification: Significant
10 Jun 2014
F o r 1 0 d a ys
(SRN)
S a n d o wn w o r k s ,
Isle of W ight.
10,200
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

S h u t d o wn t h e w o r k s .

R e p l a c e d s o d i u m h yp o c h l o r i t e s t o c k s .

P r o c e d u r e s p u t i n p l a c e f o l l o wi n g a p r e vi o u s f a i l u r e h a d
n o t b e e n f o l l o w e d a n d s t a f f we r e d i s c i p l i n e d .
Chlorate.
DWI comments and findings:

H i g h l y c r i t i c a l o f t h e d e l a y i n n o t i f yi n g t h e I n s p e c t o r a t e
a n d t h e r e p e t i t i o n o f a n a vo i d a b l e e ve n t .

R e c o m m e n d e d c o m p l i a n c e wi t h t h e B r i t i s h S t a n d a r d a n d
I n f o r m a t i o n L e t t e r 0 5 / 2 0 1 1 a n d r e q u i r e d e vi d e n c e o f h o w
t h i s wi l l b e d o n e r e l i a b l y i n f u t u r e .
Risk classification: Significant
96
London and South East region
Date and
duration
Area
11 Jun 2014
F o r 1 we e k
( T MS )
B e d w yn w o r k s ,
near
Ma r l b o r o u g h ,
W il t s h i r e .
Estimate of
population
affected
3
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Tu r b i d i t y .
Thames Water Utilities Ltd action:

Sampled affected area.

I n ve s t i g a t e d wo r k s p e r f o r m a n c e .

S a m p l e e xa m i n e d i n t h e l a b o r a t o r y c o n t a i n e d wh i t e
particles.
DWI comments and findings:

U n a c c e p t a b l e d e l a y i n n o t i f yi n g I n s p e c t o r a t e .

C r i t i c a l t h a t i n ve s t i g a t i o n d i d n o t c o n f i r m t h e p r e s e n c e o f
chalk.

R e c o m m e n d e d f u t u r e s i m i l a r i n ve s t i g a t i o n s a r e c o m p l e t e d
a s r e g a r d s e vi d e n c e o f c a u s e .

Notice put in place to require action to address ongoing
r i s k o f t u r b i d i t y b y r e m o vi n g d e p o s i t s f r o m t h e
p r e s s u r i s e d c o n t a c t t a n k s a n d i m p r o vi n g b o r e h o l e wa t e r
q u a l i t y.
Risk classification: Significant
97
Drinking water 2014
Date and
duration
Area
18 Jun 2014
For 1 hour
(SRN)
K n i g h t o n wo r k s ,
Isle of W ight.
Estimate of
population
affected
9,932
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Tu r b i d i t y d u e t o
p l a n n e d wo r k .
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

Th e a u t o s h u t d o w n wa s o ve r r i d d e n wh e n t h e w o r k s wa s
r e s t a r t e d f o l l o w i n g p l a n n e d wo r k a n d s t a f f w e r e
disciplined as a consequence.

R e vi e w i n i t i a t e d f o r s t a r t - u p p r o t o c o l s a t a l l wo r k s .
DWI comments and findings:

Th e r i s k o f t u r b i d i t y f r o m t h e h i g h l i f t p u m p m a n i f o l d wa s
n o t c o n s i d e r e d i n t h e c o m p a n y’ s d r i n k i n g w a t e r s a f e t y
plan methodology.

R e c o m m e n d e d r e vi e w o f h o w t o b e t t e r i n t e g r a t e r i s k
r e g i s t e r s t o e n s u r e s i t e s p e c i f i c h a za r d s a n d r e l a t e d
c o n t r o l m e a s u r e s a r e b e t t e r vi s u a l i s e d i n d r i n k i n g wa t e r
safety plans.

H i g h l y c r i t i c a l t h a t t h i s w a t e r q u a l i t y e v e n t wa s n o t
notified to the Inspectorate in a timely manner.

R e q u i r e d t h e c o m p a n y t o t a k e s t e p s t o p r e ve n t t h e
d e p o s i t i o n o f s e d i m e n t i n t h e d o wn s t r e a m s u p p l y n e t w o r k .

N o t i c e p u t i n p l a c e r e q u i r i n g t h e c o m p a n y t o r e vi e w a n d
resubmit its risk assessment for this works.
Risk classification: Significant
98
London and South East region
Date and
duration
Area
19 Jun 2014
F o r 4 d a ys
( A FW )
Harefield.
Estimate of
population
affected
1,150
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Ta s t e o r o d o u r d u e
t o p l a n n e d wo r k .
Affinity Water Ltd action:

Flushed mains.

R e vi e w o f p r o c e d u r e s f o r r e m e d i a t i o n o f m a i n s u s i n g i c e
pigging.

Sampled affected area.
DWI comments and findings:

V e r y c r i t i c a l t h a t t h e s i g n i f i c a n c e o f c o n s u m e r r e p o r t s wa s
not immediately recognised and customer agents had not
b e e n g i ve n a d e q u a t e b r i e f i n g n o r h a d w a t e r q u a l i t y s t a f f
b e e n i n vo l ve d i n t h e p l a n n i n g . Th i s i s a w e a k n e s s i n t h e
c o m p a n y’ s p l a n n e d w o r k r i s k a s s e s s m e n t p r o c e s s .

Recommended that all water quality calls linked to areas
w h e r e p l a n n e d wo r k i n vo l vi n g i c e p i g g i n g h a s t a k e n p l a c e
a r e i n v e s t i g a t e d i m m e d i a t e l y.

R e c o m m e n d e d t h a t c o m p a n y i m p r o ve s i t s p r o c e s s a n d
p r o c e d u r e s f o r a d va n c e w a r n i n g o f c o n s u m e r s o f p l a n n e d
work.
Risk classification: Significant
25 Jun 2014
For 1 day
( S EW )
Uckfield
15,000
South East Water Plc action:

Sampled affected a rea.

C o m p a n y f l u s h e d t h e n e t wo r k t o r e m o v e a n y r e m a i n i n g
discolouration.
B r o wn
discolouration.
DWI comments and findings:

Th i s e ve n t wa s a s h o r t - l i ve d ( 1 0 m i n u t e s ) d i s t u r b a n c e o f
mains deposits

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
99
Drinking water 2014
Date and
duration
Area
30 Jun 2014
F o r 9 d a ys
( T MS )
E a r l e y s e r vi c e
r e s e r vo i r ,
Reading.
Estimate of
population
affected
97,134
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
L o s s o f s u p p l y.
Thames Water Utilities Ltd action:

Failed to risk assess the change in how the site was
operated.

R e m o ve d t h e f l o o d w a t e r a n d r e s t o r e d p u m p i n g .

P r o vi d e d a l t e r n a t i ve s u p p l i e s ( b o t t l e d w a t e r a n d
tankered).

I n s t a l l e d n e w l e ve l p r o b e .
DWI comments and findings:

D u r i n g i m p r o ve m e n t w o r k s t o i n c r e a s e r e s e r vo i r c a p a c i t y
a b u n g wa s p l a c e d i n t h e o ve r f l o w, t h e l e ve l i n d i c a t o r
f a i l e d a n d wa t e r o ve r f l o w e d i n t o t h e b u i l d i n g d a m a g i n g
t h e b o o s t e r p u m p s a n d c a u s i n g a l o s s o f s u p p l y. Th e
s u m p p u m p wa s n o t r e p a i r e d p r o m p t l y a n d t h e b o o s t e r
f a i l e d a g a i n t e n d a ys l a t e r .

Critical that a poor risk assessment did not identify the
risk of a failed sensor.

Recommended that the company acts to ensure all
significant changes to the setup of sites are adequately
risk assessed.

Suggested that temporary changes are entered into the
c o n t r o l r o o m s ys t e m t o m a k e c o n t r o l r o o m s t a f f a wa r e o f
changes in the mode of operation.
Risk classification: Significant
100
London and South East region
Date and
duration
Area
03 Jul 2014
For 3 hours
(PRT)
Gosport.
Estimate of
population
affected
139,203
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Loss of supply due
t o p l a n n e d wo r k .
Portsmouth Water Plc action:

Repaired mains and PRV.

Sampled some but not all of the affected area.
DWI comments and findings:

Th i s e ve n t o f m u l t i p l e b u r s t s d u r i n g a p l a n n e d i n s p e c t i o n
o c c u r r e d wh e n a p r e s s u r e r e d u c i n g va l ve f a i l e d r e s u l t i n g
in a burst main.

C r i t i c a l t h a t r i s k a s s e s s m e n t f o r t h e p l a n n e d wo r k h a d n o
contingency for a PRV failure .

R e c o m m e n d e d t h a t t h e c o m p a n y r e vi e w s i t s p r o c e d u r e s
for collecting sufficient and appropriate samples .

S u g g e s t e d t h a t t h e c o m p a n y r e vi e w s i t s p o l i c y f o r r i s k
a s s e s s m e n t s o f p l a n n e d w o r k a n d m a k e s i m p r o ve m e n t s t o
e n s u r e l e a r n i n g f r o m t h i s e ve n t .
Risk classification: Significant
101
Drinking water 2014
Date and
duration
Area
05 Jul 2014
For 3 months
( T MS )
Henley-onTh a m e s .
Estimate of
population
affected
10
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Odour –
h yd r o c a r b o n s .
Thames Water Utilities Ltd action:

Issued do not drink (DND) notice to householders
e xp e r i e n c i n g a n o i l l i k e t a s t e / o d o u r .

P r o vi d e d b o t t l e d wa t e r .

Sampled affected area.

O b t a i n e d h e a l t h a d vi c e o n h yd r o c a r b o n s f o u n d .

Changed procedure for issuing DND notices.
DWI comments and findings:

C r i t i c a l t h a t D N D n o t i c e s we r e n o t g i ve n t o t h r e e
p r o p e r t i e s w h e r e n o b o d y a n s we r e d t h e d o o r .

R e c o m m e n d e d t h a t t h e c o m p a n y d e l i ve r s a wr i t t e n n o t i c e
to all affected properties rather than rely on door
knocking.

C r i t i c a l t h a t t h e c o m p a n y r e s c i n d e d s o m e n o t i c e s wi t h o u t
reference to sample results and had to reinstate them .

R e c o m m e n d e d t h a t w h e r e c o n s u m e r s h a ve c o n t a c t e d t h e
water company with a taste or odour complaint that
s a m p l e s a r e a n a l ys e d a s s o o n a s p o s s i b l e .

Suggested putting in place procedures to enable prompt
f i t t i n g s i n s p e c t i o n s a n d e f f e c t i ve c o n s u m e r s u p p o r t f o r
s i t u a t i o n s wh e r e s e r vi c e p i p e r e p l a c e m e n t i s t h e
p e r m a n e n t r e m e d y t o a n e ve n t .
Risk classification: Significant
102
London and South East region
Date and
duration
Area
17 Jul 2014
For 10 hours
( S EW )
S e ve n o a k s , K e n t .
Estimate of
population
affected
1,750
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Me d i a i n t e r e s t d u e
to discolouration
caused by planned
work.
South East Water Plc action:

W ar n i n g n o t i c e s w e r e s u p p l i e d t o c o n s u m e r s a h e a d o f
t h i s p l a n n e d wo r k t o i n s t a l l n e w va l ve s o n s u p p l y t o a n e w
d e ve l o p m e n t .

Flushed mains.

Sampled affected area.

Issued a press statement.

R e vi e w o f p r o c e d u r e s .
DWI comments and findings:

Flushing in preparation for planned work caused
discolouration and this was reported in the local
n e ws p a p e r .

Recommended that the company put in place
arrangements to ensure that risks are appropriately
i d e n t i f i e d a n d m i t i g a t e d i n a d va n c e o f p l a n n e d w o r k ,
t h r o u g h t h e u s e o f n e t w o r k m o d e l s wh e r e a p p r o p r i a t e .
Risk classification: Significant
103
Drinking water 2014
Date and
duration
Area
21 Jul 2014
For 4 months
(SRN)
Isle of W ight.
Estimate of
population
affected
10
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
A d vi c e t o b o i l
water.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

I n ve s t i g a t e d t h e p r e vi o u s l y u n k n o wn c o n c e s s i o n a r y
s u p p l y f r o m a s p r i n g b y r e vi e w i n g l a n d r e g i s t r y r e c o r d s .

I s s u e d b o i l wa t e r n o t i c e s .

P r o vi d e d b o t t l e d wa t e r .

S a m p l e d t h e s u p p l y.

Erected temporary fencing to protect the source.

Connected the properties to the public water supply
s ys t e m .
DWI comments and findings:

Th i s e ve n t c a m e a b o u t a s a r e s u l t o f t h e d i s c o ve r y o f a
h i t h e r t o u n k n o w n c o n c e s s i o n a r y s u p p l y.

C r i t i c a l t h a t b o i l wa t e r n o t i c e wa s n o t i s s u e d i n a t i m e l y
manner.

Recommended that boil water notices are issued jointly
wi t h t h e l o c a l a u t h o r i t y w h e r e t h e r e i s u n c e r t a i n t y o ve r a
g i ve n w a t e r s u p p l y a r r a n g e m e n t a s r e g a r d s i t s s t a t u s a s a
p u b l i c o r p r i va t e w a t e r s u p p l y .

Commended the company for their pro -bono connections
t o t h e wa t e r s u p p l y s ys t e m a s t h e m e a n s o f p r o v i d i n g a
p e r m a n e n t r e m e d y.
Risk classification: Significant
21 Jul 2014
F o r 8 we e k s
( A FW )
Bagshot, Surrey.
150
Coliforms
f o l l o wi n g t h e
repair of a burst
main.
Affinity Water Ltd action:

I n ve s t i g a t i o n a l s a m p l i n g a n d f l u s h i n g o f m a i n .

Fittings inspection at a hotel fed by the main.

W id e r s a m p l i n g , c h l o r i n a t i o n a n d a d vi c e g i ve n t o t h e
hotel.

S t a f f i n vo l ve d i n t h e e ve n t we r e g i ve n a d vi c e .
DWI comments and findings:

Critical of how the flushing operations were carried out,
company confirmed that staff had been retrained.
Risk classification: Significant
104
London and South East region
Date and
duration
Area
22 Jul 2014
For 6 minutes
(SRN)
F l e m i n g s wo r k s ,
Deal, Kent.
Estimate of
population
affected
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Disinfection
failure.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

F o l l o wi n g a U V t u b e f a i l u r e t h e c o m p a n y f o u n d t h a t a
b o r e h o l e wa s s t i l l r u n n i n g f o r s i x m i n u t e s a f t e r t h e a l a r m
a n d b e f o r e t h e s i t e s h u t d o wn .

No undisinfected water left site and any that passed
t h r o u g h t h e p r o c e s s wa s f l u s h e d a wa y f r o m t h e c o n t a c t
main.
DWI comments and findings:

Commended the company for its precautionary response
t o t h e e ve n t .

Suggested shutdown tests are carried out more frequently
t h a n a n n u a l l y.

S u g g e s t e d t e l e m e t r y s c a n t i m e s a r e r e vi e w e d a n d s e t a t
the same frequency for all boreholes.

R e c o m m e n d e d t h e c o m p a n y i n ve s t i g a t e t h e c a u s e o f a i r
in the monitors on start-up and apply remedial action to
ensure that false high turbidity readings no longer oc cur.

R e c o m m e n d e d t h e c o m p a n y c a r r i e s o u t a r e vi e w o f o t h e r
works to ensure that similar false high turbidity readings
do not occur.

R e c o m m e n d e d t h a t t h e c o m p a n y r e vi e w a n d u p d a t e t h e
r e g u l a t o r y r i s k a s s e s s m e n t s i n l i g h t o f t h i s e ve n t l e a r n i n g .
Risk classification: Significant
28 Jul 2014
F o r 2 we e k s
(SSE/ALS
W ak e f i e l d )
Chichester.
None
ALS W akefield.
SSE Water action:

L a b o r a t o r y m e t h o d f o r 2 , 3 , 6 - t r i c h l o r o b e n zo i c a c i d
p r o d u c e d a n o m a l o u s r e s u l t s a n d wa s a m e n d e d t o p r e v e n t
reoccurrence.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
105
Drinking water 2014
Date and
duration
Area
30 Jul 2014
F o r 2 we e k s
(SRN)
W ei r W o o d
w o r k s , C r a wl e y,
W es t S u s s e x .
Estimate of
population
affected
33,750
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Chlorate.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

D r a i n e d s o d i u m h yp o c h l o r i t e a n d r e p l e n i s h e d s t o c k s .

R e vi s e d p r o c e d u r e t o d r a i n s t o c k i m m e d i a t e l y p r i o r t o
d e l i ve r y.

Audited supplier and found deficiencies in traceability and
n o n - c o m p l i a n c e wi t h t h e r e q u i r e m e n t s o f t h e B r i t i s h
S t a n d a r d Me t h o d f o r c h l o r a t e a n a l ys i s i n s o d i u m
h yp o c h l o r i t e .

Reintroduced cooling on the storage tanks.

L i a i s e d wi t h n e i g h b o u r i n g c o m p a n y a b o u t b u l k s u p p l y.
DWI comments and findings:

R e p e a t o f a n e ve n t t h a t o c c u r r e d o n 2 6 J u l 2 0 1 2 ( s e e
Drinking water 2012 – Annex 3).

F o l l o wi n g a n e ve n t i n 2 0 1 2 t h e c o m p a n y h a d t a k e n s t e p s
t o r e d u c e s t o c k h o l d i n g o n s i t e a n d i n c r e a s e t u r n o ve r o f
s o d i u m h yp o c h l o r i t e c o m b i n e d wi t h a n e n h a n c e d
monitoring strategy for chlorate.

Critical that cooling equipment on the bulk storage tanks
had not been maintained.

Notice put in place to address risks from chlorate at all of
t h e c o m p a n y’ s s i t e s .
Risk classification: Serious
106
London and South East region
Date and
duration
Area
04 Aug 2014
F o r 1 we e k
( T MS )
Islip,
O xf o r d s h i r e .
Estimate of
population
affected
37,500
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Coliforms.
Thames Water Utilities Ltd action:

I n c r e a s e d c h l o r i n e r e s i d u a l i n t h e zo n e .

Sampled affected area.

Flushed mains.

Ma n a g e d s t o r a g e l e ve l s i n s u p p l yi n g s e r vi c e r e s e r vo i r .
DWI comments and findings:

Mu l t i p l e c o l i f o r m f a i l u r e s i n o n e vi l l a g e wh i c h c e a s e d
when chlorine residual was increased.

Critical that a long-term strategy for managing chlorine
r e s i d u a l s i n t h i s s u p p l y a r e a wa s n o t d e ve l o p e d .

R e c o m m e n d e d t h a t t h e c o m p a n y d e ve l o p a p e r m a n e n t
r e m e d y a n d p r o vi d e d e t a i l s t o t h e I n s p e c t o r a t e .
Risk classification: Significant
07 Aug 2014
F o r 8 5 d a ys
( T MS )
K e n s a l To wn ,
W es t L o n d o n .
3
Thames Water Utilities Ltd action:

I s s u e d a b o i l wa t e r n o t i c e .

Carried out a water fittings inspection .

Issued a Section 75 Enforcement Notice on the garage
o wn e r .

S u b s e q u e n t l y ve r i f i e d t h a t t h e o wn e r o f t h e g a r a g e h a d
r e m e d i e d t h e f a u l t s ( b a c k f l o w p r o t e c t i o n a n d r e m o va l o f
redundant pipework).
Coliforms.
DWI comments and findings:

S a m p l i n g wa s n o t t i m e l y e n o u g h .

Suggested that the company takes steps to lift boil
notices as soon as practicable.
Risk classification: Significant
107
Drinking water 2014
Date and
duration
Area
13 Aug 2014
F o r 1 4 d a ys
( S EW )
Ma i d e n b o w e r ,
S u s s e x.
Estimate of
population
affected
12,752
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Notification of
chlorate issue
affecting bulk
supply from
Southern W ater.
South East Water Plc action:

L i a i s e d wi t h S o u t h e r n W a t e r .

Sampled affected area.
DWI comments and findings:

R e c o m m e n d e d b u l k s u p p l y a g r e e m e n t i n p l a c e b e t we e n
b o t h c o m p a n i e s i s i m p r o ve d .
Risk classification: Significant
15 Aug 2014
For 12 hours
(SES)
E l m e r wo r k s ,
Leatherhead,
Surrey.
170,000
Sutton and East Surre y Water Plc action:

Th e c o m p a n y r e d u c e d o u t p u t f r o m t h e s i t e a n d c o n t i n u e d
s u p p l y wi t h wa t e r t h a t w a s d i s i n f e c t e d u s i n g t h e o t h e r
functional UV reactor on site .

I d e n t i f i e d a n d r e c t i f i e d a s o f t wa r e f a u l t .
Disinfection
failure.
DWI comments and findings:

A f a u l t o n t h e U V d i s i n f e c t i o n s ys t e m f a i l e d t o i n i t i a t e
a l a r m s o r f a i l s a f e s h u t d o wn a n d t h e wo r k s c o n t i n u e d t o
s u p p l y f o r o ve r 1 1 h o u r s b e f o r e a c t i o n w a s t a k e n .

F a i l e d t o c a r r y o u t a p p r o p r i a t e i n ve s t i g a t i ve s a m p l i n g .

Recommended that the company carries out appropriate
i n ve s t i g a t i o n s e n s u r i n g t h e a p p r o p r i a t e n u m b e r a n d t yp e
o f s a m p l e s a r e t a k e n t o d e m o n s t r a t e t h e e xt e n t a n d
nature of any water quality impact.
Risk classification: Significant
16 Aug 2014
For 1 day
( A FW )
Kings W alden
w o r k s , O f f l e y,
Kimpton.
6,400
Tr e a t m e n t f a i l u r e
– nitrate.
Affinity Water Ltd action:

Sampled affected area.

Ma d e c h a n g e s t o s o f t wa r e s e t t i n g s c o n t r o l l i n g b l e n d i n g s o
they cannot be altered.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
108
London and South East region
Date and
duration
Area
21 Aug 2014
F o r 3 0 d a ys
(SRN)
Isle of W ight.
Estimate of
population
affected
1,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
B r e a k - i n a t wo r k s .
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

R e m o ve d wo r k s f r o m s u p p l y f o l l o w i n g b r e a k - i n a n d
carried out sampling.

Th e c o m p a n y a r e u p g r a d i n g t h e s i t e s e c u r i t y w h i c h wa s
s c h e d u l e d t o b e c o m p l e t e d b y Ma r c h 2 0 1 5 b u t h a s b e e n
d e l a ye d b y t h r e e m o n t h s ( s e e A n n e x 4 . 1 ) .
DWI comments and findings:

E n f o r c e m e n t i n i t i a t e d t o p r o t e c t r a w wa t e r s o u r c e .
Risk classification: Significant
21 Aug 2014
F o r 2 we e k s
( A FW )
R i n g wo u l d , K e n t .
3
Ta s t e o r o d o u r –
petrol.
Affinity Water Ltd action:

Flushed mains.

Retrained staff.

Sampled affected area.
DWI comments and findings:

Q u e r i e d t h e c o m p a n y’ s r e c o r d k e e p i n g i n r e l a t i o n t o v a l ve
o p e r a t i o n s . Th e I n s p e c t o r a t e wa s s u b s e q u e n t l y s a t i s f i e d
wi t h t h e c o m p a n y’ s a c t i o n s .
Risk classification: Significant
109
Drinking water 2014
Date and
duration
Area
24 Aug 2014
For 24 hours
( T MS )
Kangley Bridge
works,
Beckenham and
Bromley.
Estimate of
population
affected
100,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Coliforms.
Thames Water Utilities Ltd action:

Sampled affected area.

R e m o ve d wo r k s f r o m s u p p l y.

R e vi e w e d t r e a t m e n t p r o c e s s .

Identified ingress into the balance tank and made repairs.
DWI comments and findings:

A Notice was already in place requiring the company to
a d d r e s s i n g r e s s p r o b l e m s a n d f i l t e r p e r f o r m a n c e f o l l o wi n g
a microbiological failure in 2012 .

C r i t i c a l t h a t a p p r o p r i a t e m a n a g e m e n t s ys t e m s w e r e n o t i n
place to ensure that the remediation in 2012 was fit for
purpose.

R e c o m m e n d e d a r e vi e w o f c o n t r a c t o r c o n t r o l p r o c e d u r e s
and required details of how future remedial work is to be
ve r i f i e d a s f i t f o r p u r p o s e .

Inspections of the chemical dosing chamber, as required
b y a p r e vi o u s a u d i t , w e r e f o u n d n o t t o h a ve b e e n c a r r i e d
out and the wrong buffer had been used on chlorine
monitors.

H yp o c h l o r i t e d o s i n g p u m p wa s n o t w o r k i n g ( d u e t o
missing rubbers and rollers); and the pH me ters had not
b e e n s e r vi c e d o r c a l i b r a t e d s i n c e J a n u a r y 2 0 1 4 .

Recommended the company demonstrate that these
maintenance issues had no impact on disinfection.

Orthophosphate dosing was not operational for a month
leading up to the event in contravention of a companywi d e N o t i c e i n p l a c e f o r t r e a t m e n t t o a d d r e s s t h e r i s k
from lead.

Recommended the company demonstrates that the lack of
p h o s p h a t e d o s i n g h a d n o t h a d a n y a d ve r s e i m p a c t o n l e a d
compliance.

N o t i c e wa s a m e n d e d t o r e q u i r e t h e c o m p a n y t o a d d r e s s
t h e f a i l i n g s r e ve a l e d b y t h i s e ve n t .
Risk classification: Serious
110
London and South East region
Date and
duration
Area
29 Aug 2014
For 24 hours
( S EW )
Farnham, Surrey.
Estimate of
population
affected
7,500
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
B r o wn
discolouration due
t o p l a n n e d wo r k .
South East Water Plc action:

Sampled affected area.

Mo d e l l e d t h e c a u s e p o s t e ve n t b u t u n a b l e t o t e s t f i n d i n g s
b e c a u s e o f l a c k o f h i g h w a ys a c c e s s .
DWI comments and findings:

Th i s e ve n t wa s c a u s e d b y a l a c k o f k n o wl e d g e a b o u t t h e
n e t wo r k c o n f i g u r a t i o n r e s u l t i n g i n i n c r e a s e d ve l o c i t y a n d
scouring of the main lifting deposits.

Recommended that the planning of planned flushing
o p e r a t i o n s i n vo l ve s t e p s t o m i t i g a t e t h e r i s k o f c h a n g i n g
m a i n s ve l o c i t i e s a n d a c c u r a t e i n f o r m a t i o n g i ve n t o t h o s e
c a r r yi n g o u t t h e wo r k .
Risk classification: Significant
29 Aug 2014
For 24 hours
( S EW )
Halling, Kent.
10,000
B r o wn
discolouration due
to mains burst.
South East Water Plc action:

Repaired main.

Flushed mains.

Sampled affected area.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
111
Drinking water 2014
Date and
duration
Area
05 Sep 2014
F o r 1 we e k
( T MS )
Chingford,
London.
Estimate of
population
affected
3
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Do not drink notice
– cross connection
t o r a i n wa t e r
h a r ve s t i n g s ys t e m .
Thames Water Utilities Ltd action:

F o l l o wi n g a c o m p l a i n t o f a n u n u s u a l ‘ e g g y’ o d o u r c a r r i e d
out a fittings inspection and identified a cross connection
t o a r a i n w a t e r h a r ve s t i n g s ys t e m .

Issued a do not drink notice.

A d vi s e d c o n s u m e r t o c o n s u l t a p l u m b e r t o r e c t i f y c r o s s
connection issues.

B o i l n o t i c e l i f t e d a f t e r p l u m b i n g wo r k c o m p l e t e .
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
12 Sep 2014
F o r 8 we e k s
( S EW )
Godmersham
s e r vi c e r e s e r v o i r ,
Ashford, Kent.
32,000
Risk classification: Significant
South East Water Plc action:

R e m o ve d r e s e r vo i r f r o m s u p p l y.

Sampled affected area.

C h a n g e d c o m b i n e d i n l e t / o u t l e t a r r a n g e m e n t t o i m p r o ve
turnover.
E.coli.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
19 Sep 2014
F o r 1 we e k
(PRT)
Bosham,
Chichester.
5
Risk classification: Significant
Portsmouth Water Plc action:

Identified a section of old coal tar lined main.

Scheduled replacement of main in 2015 and put in place
regular flushing as an interim precautionary measure.

Sampled affected area.
P o l yc yc l i c
aromatic
h yd r o c a r b o n s .
DWI comments and findings:

Th i s e ve n t r e l a t e d t o d e t e r i o r a t i o n o f a s e c t i o n o f c o a l t a r
lined main.

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
112
London and South East region
Date and
duration
Area
23 Sep 2014
F o r 4 d a ys
( T MS )
O xf o r d .
Estimate of
population
affected
125
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Me d i a i n t e r e s t d u e
to mains burst.
Thames Water Utilities Ltd action:

Isolated and repaired main.

Sampled affected area.

Communicated about the cause of the flooding .

P l a n s i n p l a c e t o r e p l a c e 2 k m o f m a i n t o p r e ve n t a
recurrence.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
24 Sep 2014
For 24 hours
(SRN)
W oo t t o n B r i d g e ,
Isle of W ight.
88
Illness linked to
Pseudomonas.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

F o l l o wi n g a n o t i f i c a t i o n o f i l l n e s s b y l o c a l e n vi r o n m e n t a l
health, carried out a fittings i nspection at the holiday park
and identified a number of issues including a new ring
m a i n i n s t a l l e d t o c a b i n s wi t h o u t a n a p p r o p r i a t e
disinfection certificate.

S e r ve d a S e c t i o n 7 5 N o t i c e t o t h e o wn e r w h o t h e n m a d e
t h e n e c e s s a r y i m p r o ve m e n t s .
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
113
Drinking water 2014
Date and
duration
Area
30 Sep 2014
For 1 day
( T MS )
W al t o n wo r k s ,
Greater London.
Estimate of
population
affected
97,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Bromate.
Thames Water Utilities Ltd action:

Sampled affected area.

O zo n e d o s i n g s h u t d o w n u n t i l f u l l r e vi e w o f p r o c e d u r e s
completed.
DWI comments and findings:

Inadequate procedures relating to the management of
o zo n e d o s i n g .

Recommended that procedures are put in place regarding
the calibration and maintenance of equipment as this is a
r e p e t i t i o n o f o zo n e d o s i n g p r o b l e m s a t t h i s w o r k s .
Risk classification: Significant
114
London and South East region
Date and
duration
Area
13 Oct 2014
For 1 day
( T MS )
Bishops Green
works, Newbury.
Estimate of
population
affected
101,875
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Coliforms.
Thames Water Utilities Ltd action:

I n ve s t i g a t i o n f o u n d w a t e r p o o l i n g o n c o n t a c t t a n k r o o f d u e
to leaf litter blocking drains and risk of ingress of surface
water into borehole.

Th e c o m p a n y r e m o ve d t h e l e a f l i t t e r a n d c l e a r e d t h e
drains.

O n e h a l f o f t h e c o n t a c t t a n k wa s d r a i n e d f o r i n s p e c t i o n
a n d wa s r e p a i r e d a n d c l e a n e d a f t e r s e ve r a l p o i n t s o f
i n g r e s s we r e i d e n t i f i e d .

Plans in place to inspect the second compartment as soon
as is practicable.
DWI comments and findings:

Similar ingress risks noted at this site in 2011 and 2012
a n d c r i t i c a l o f t h e c o m p a n y f o r n o t l e a r n i n g f r o m p r e vi o u s
e ve n t s e . g . D a n c e r s E n d .

Recommended that the company assess the growth of
f l o r a a r o u n d t h e c o n t a c t t a n k a n d i m p r o ve m a i n t e n a n c e t o
minimise the risk of ingress to the structure.

S u g g e s t e d t h a t t h e c o m p a n y c a r r i e s o u t a r e vi e w o f a l l i t s
c o n t a c t t a n k s a n d f o r r i s k o f o ve r g r o w n f l o r a .

Suggested the company instigates a programme of audits
to improve site operator training an d performance in
r e l a t i o n t o w a t e r s u p p l y h yg i e n e a c t i vi t i e s .

R e c o m m e n d e d t h e c o m p a n y r e vi e w s i t s p o l i c y a n d a d o p t s
a risk-based approach to inspections as opposed to a
g e n e r i c 1 0 - ye a r l y i n s p e c t i o n r e g i m e .

Suggested the company completes all outstanding
i n s p e c t i o n s a t t h e e a r l i e s t o p p o r t u n i t y.
Risk classification: Significant
115
Drinking water 2014
Date and
duration
Area
23 Oct 2014
F o r 3 d a ys
( T MS )
D e p t f o r d wo r k s ,
Deptford,
London.
Estimate of
population
affected
135,000
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Tr e a t m e n t f a i l u r e
– turbidity.
Thames Water Utilities Ltd action:

Sampled affected area.

R e m o ve d wo r k s f r o m s u p p l y .

D r a i n e d c o n t a c t t a n k s a n d r e m o ve d s i g n i f i c a n t a m o u n t s o f
sediment.

Installed post contact tank turbidimeter .
DWI comments and findings:

C r i t i c a l t h a t t h e c a u s e o f t h e s e d i m e n t d i s t u r b a n c e wa s
n o t i n ve s t i g a t e d a n d i d e n t i f i e d .
Risk classification: Significant
07 Nov 2014
For 18 hours
(SES)
South Redhill,
S u r r e y.
5,833
Loss of supply due
t o p l a n n e d wo r k .
Sutton and East Surre y Water Plc action:

W he n p l a n n e d wo r k t o r e m o ve 2 0 0 m o f m a i n c a u s e d a
n u m b e r o f b u r s t s t h e c o m p a n y p r o a c t i ve l y c o n t a c t e d a
hospital in the affected area to ensure supplies were
maintained.

Supplied bottled water on request.

Procedures changed to specify a resample from the same
property following a failure.
DWI comments and findings:

Although sampling was carried out, it did not include
resampling from the original property where a high iron
result had been reported.

Recommended company takes steps to ensure property s p e c i f i c i s s u e s a r e n o t o ve r l o o k e d w h e n r e s p o n d i n g t o
d i s t r i b u t i o n - r e l a t e d e ve n t s .
Risk classification: Significant
116
London and South East region
Date and
duration
Area
10 Nov 2014
F o r 4 d a ys
( S EW )
Bracknell, Berks.
Estimate of
population
affected
27,500
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Air in water
( wh i t e ) d u e t o
mains burst.
South East Water Plc action:

Repaired main.

Flushed mains.

R e zo n e d a r e a ( b r o u g h t i n wa t e r f r o m d i f f e r e n t s o u r c e ) .

Sampled affected area.
DWI comments and findings:

Inadequate number of samples taken and company will be
r e vi e w i n g p r o c e d u r e s s o t h a t p o s t e ve n t s a m p l i n g i s
i m p r o ve d .
Risk classification: Significant
11 Nov 2014
For 24 hours
(SRN)
Mi l e O a k wo r k s ,
Portslade, nr
B r i g h t o n , W es t
S u s s e x.
25,267
Tr e a t m e n t f a i l u r e
– t u r b i d i t y.
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

S h u t d o wn t r e a t m e n t wo r k s .

Sampled affected area.

R e m o ve d wo r k s f r o m s u p p l y u n t i l r a w wa t e r q u a l i t y
returned to normal.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
12 Nov 2014
F o r 3 d a ys
( T MS )
C o l d A s h s e r vi c e
r e s e r vo i r ,
Th a t c h a m ,
N e wb u r y .
17,500
Loss of supply due
to mains burst.
Thames Water Utilities Ltd action:

Supplied bottled water.

B u r s t o c c u r r e d o n i n l e t t o r e s e r vo i r s o t h e b o o s t e r wa s
b yp a s s e d a n d s u p p l y w a s i n c r e a s e d f r o m a n o t h e r wo r k s
to partially restore supplies .

Repaired main.

Sampled affected area.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
117
Drinking water 2014
Date and
duration
Area
24 Nov 2014
F o r 3 d a ys
( T MS )
S wa n l e y, K e n t .
Estimate of
population
affected
60,833
Nature and cause
o f t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
B r o wn
discolouration due
to mains burst.
Thames Water Utilities Ltd action:

Flushed mains.

Repaired main.

Sampled affected area.

Staff briefed on correct procedures.
DWI comments and findings:

C o m p a n y a c k n o wl e d g e d t h a t p r o c e d u r e s w e r e n o t
f o l l o we d c o r r e c t l y t o m i n i m i s e d i s c o l o u r a t i o n i n t h i s
k n o wn p r o b l e m a r e a .
Risk classification: Significant
25 Nov 2014
For 1 month
(SES)
Chipstead,
Surrey.
6,500
Loss of supply due
to third party
mains damage.
Sutton and East Surre y Water Plc action:

P r o vi d e d b o t t l e d wa t e r .

Mo n i t o r e d t u r b i d i t y t o a s s e s s c a u s e .

P l a n n e d t o r e m o ve c h a l k d e p o s i t s u s i n g i c e p i g g i n g
technique.

P l a n n e d t o r e p l a c e a s e c t i o n o f o ve r - s i ze d m a i n .
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
31 Dec 2014
For 1 day
( T MS )
N u n h e a d s e r vi c e
r e s e r vo i r , S o u t h
London.
400,000
Thames Water Utilities Ltd action:

Sampled affected area.

I n s p e c t e d r e s e r vo i r a n d f o u n d n o d e f e c t s , l i k e w i s e n o
r e l e va n t d i s t r i b u t i o n e v e n t s i d e n t i f i e d .

C o n s u l t e d P H E . N o e vi d e n c e o f i l l n e s s wi t h i n t h e
c o m m u n i t y.
E.coli.
DWI comments and findings:

Th e I n s p e c t o r a t e w a s s a t i s f i e d wi t h t h e c o m p a n y ’ s
h a n d l i n g o f t h i s e ve n t .
Risk classification: Significant
118
London and South East region
Events in the London and South E ast region outstanding from 2013 completed in 2014
Date and
duration
Area
24 Dec 2013
For 4 hours
(SRN)
Coltstable
r e s e r vo i r
Horsham, W est
S u s s e x.
Estimate of
population
affected
10,000
Nature and cause of
t h e e ve n t
Main actions and findings from the Inspectorate
i n ve s t i g a t i o n
Loss of supply due
t o p o we r f a i l u r e .
S o u t h e r n W a t e r S e r vi c e s L t d a c t i o n :

Sampled affected area.

R e zo n e d t h e a r e a ( b r o u g h t wa t e r i n f r o m a n o t h e r a r e a ) .
DWI comments and findings:

A d ve r s e we a t h e r c a u s e d l o s s o f p o we r a n d t h e n t h e
l o s s o f t e l e m e t r y c o m m u n i c a t i o n t o t h e r e s e r vo i r . P o we r
w a s n o t r e s t o r e d f o r s e v e r a l d a ys r e s u l t i n g i n i m p a i r e d
c o n t r o l o f t h e r e s e r vo i r .

C o m p a n y h a s t r i a l l e d n e w b r o a d b a n d s o f t wa r e t o
i m p r o ve t h e r e l i a b i l i t y o f c o m m u n i c a t i o n s wi t h s i t e .
Risk classification: Significant
No te : A c om p le t e ta b l e of e ve nts in En g l an d a n d W ales in 2 0 14 c a n b e f o u nd o n t he DW I webs i te ( ww w. d wi .d ef ra. g o v. uk ) .
It is n am ed Sig nif ic an t d rin ki ng w at e r ev e n ts in E ngl an d and W a le s 2 01 4 .pdf .
119
Drinking water 2014
Annex 4
Planned drinking water quality improvements
Company
Parameter,
h a z a r d o r d r i ve r
Site
Due for
completion*
Status*
Legal
Instrument
A FW
Lead
Distribution
S ys t e m
3 1 - Ma r - 2 0
Ongoing
Notice
A FW
Ma n g a n e s e
Blackford
30-Jun-14
D e l a ye d
Undertaking
A FW
Ma n g a n e s e
R o yd o n
3 1 - Ma r - 1 4
D e l a ye d
Undertaking
A FW
Me t a l d e h yd e
Bulk Imports
3 1 - Ma r - 2 0
Ongoing
Undertaking
A FW
Nitrate
3 1 - Ma r - 1 4
Completed
2 8 - Ma r - 1 4
Undertaking
A FW
Pesticides and
m e t a l d e h yd e
3 1 - Ma r - 2 0
Ongoing
Undertaking
A FW
Pesticides,
carbetamide,
p r o p y za m i d e a n d
m e t a za c h l o r
I ve r
3 1 - Ma r - 1 8
Ongoing
Notice
IW N
Pesticides
Kings Cross
3 1 - Ma r - 1 5
Completed
3 1 - Ma r - 1 5
Undertaking
Eastergate
31-Aug-16
Ongoing
Notice
W es t e r g a t e
31-Aug-16
Ongoing
Notice
3 1 - Ma r - 2 0
Ongoing
Notice
3 1 - Ma r - 1 5
Ongoing
Undertaking
Bough Beech
3 1 - Ma r - 2 0
Ongoing
Undertaking
Stockbury
31-Dec-16
Ongoing
Notice
W at e r wo r k s
Road
3 1 - Ma r - 1 6
Ongoing
Notice
PRT
PRT
Cryptosporidium
and turbidity
Cryptosporidium
and turbidity
PRT
Lead
SES
Lead
SES
Me t a l d e h yd e
S EW
S EW
Coliform bacteria
and E.coli
Coliform bacteria
and E.coli
Kings
W al d e n
R i ve r
Th a m e s
treatment
works
Lead
strategy
Distribution
s ys t e m
S EW
Cryptosporidium
Arlington
3 1 - Ma r - 1 4
S EW
Cryptosporidium
Barcombe
3 1 - Ma r - 1 4
S EW
Cryptosporidium
C r o wh u r s t
Bridge
3 1 - Ma r - 1 4
S EW
Cryptosporidium
Friston
3 1 - Ma r - 1 4
S EW
Cryptosporidium
G r e y we l l
3 1 - Ma r - 1 4
S EW
Cryptosporidium
H a za r d s
Green
3 1 - Ma r - 1 5
S EW
Ingress
St Lawrence
3 1 - Ma r - 1 5
S EW
Iron
Ashford
3 1 - Ma r - 1 5
120
Completed
2 7 - Ma r - 1 4
Completed
21-Jan-14
Completed
2 6 - Ma r - 1 4
Completed
3 1 - Ma r - 1 4
Completed
2 6 - Ma r - 1 4
Completed
1 6 - Ma r - 1 5
Completed
11-Apr-11
Completed
2 5 - Ma r - 1 5
Notice
Notice
Notice
Notice
Notice
Notice
Notice
Undertaking
London and South East region
Company
S EW
S EW
S EW
S EW
Parameter,
h a z a r d o r d r i ve r
New raw water
main –
Cryptosporidium
Pesticides and
m e t a l d e h yd e
Pesticides and
m e t a l d e h yd e
Pesticides and
m e t a l d e h yd e
Site
Due for
completion*
Status*
Legal
Instrument
Filching
3 1 - Ma r - 1 4
Completed
21-Feb-14
Notice
Bulk Imports
3 1 - Ma r - 2 0
Ongoing
Undertaking
3 1 - Ma r - 1 5
Completed
3 1 - Ma r - 1 5
Undertaking
3 1 - Ma r - 2 0
Ongoing
Undertaking
C r o wh u r s t
Bridge
Catchment
management
S EW
Tu r b i d i t y
Birling Farm
31-Dec-12
Completed
23-Oct-14
Notice
S EW
Tu r b i d i t y
Kingston
31-Aug-16
Ongoing
Notice
S EW
Tu r b i d i t y
Rathfinney
3 1 - Ma r - 1 2
Completed
08-Jan-14
Notice
SRN
Bacteriological
Lord of the
Ma n o r
30-Nov-15
Ongoing
Notice
SRN
Bacteriological
Ventnor
3 1 - Ma r - 1 5
D e l a ye d
Notice
SRN
SRN
SRN
SRN
SRN
SRN
Inadequate
disinfection
Inadequate
disinfection
Inadequate
disinfection
Inadequate
disinfection
Inadequate
disinfection
Inadequate
disinfection
Calbourne
3 1 - Ma r - 1 5
Chillerton
3 1 - Ma r - 1 5
Gore
31-Oct-16
Hardham
31-Dec-14
Mi n s t e r
30-Apr-16
Shoreham
3 1 - Ma r - 1 5
Completed
19-Feb-15
Completed
13-Feb-15
O n Ta r g e t
Completed
31-Dec-14
Completed
01-Apr-14
Completed
22-Dec-14
Notice
Notice
Notice
Notice
Notice
Notice
SRN
Iron
W oo l m a n s
W oo d
31-Nov-18
Ongoing
Undertaking
SRN
Nitrate
Burpham
30-Sep-16
Ongoing
Notice
SRN
Nitrate
Chilbolton
30-Sep-16
Ongoing
Notice
SRN
Nitrate
Findon
30-Sep-16
Ongoing
Notice
SRN
Nitrate
Gore
30-Sep-16
Ongoing
Notice
SRN
Nitrate
Shoreham
30-Sep-16
Ongoing
Notice
SRN
Nitrate
Sompting
30-Sep-16
Ongoing
Notice
Pesticides and
m e t a l d e h yd e
Ta s t e , o d o u r ,
pesticides and
trihalomethanes
Ta s t e , o d o u r ,
pesticides and
trihalomethanes
Pesticides and
m e t a l d e h yd e
Catchment
management
3 1 - Ma r - 2 0
Ongoing
Undertaking
Beauport
3 1 - Ma r - 1 8
Ongoing
Notice
Brede
30-Sep-18
Ongoing
Notice
All sites
3 1 - Ma r - 2 0
O n Ta r g e t
Undertaking
T MS
Chlortoluron
Harpsden
3 1 - Ma r - 1 5
T MS
Coliform bacteria
Kidderpore
3 1 - Ma r - 1 5
SRN
SRN
SRN
SSE
121
Completed
3 1 - Ma r - 1 5
Completed
4 - Ma r - 1 5
Undertaking
Notice
Drinking water 2014
Company
T MS
T MS
Parameter,
h a z a r d o r d r i ve r
Coliform bacteria
and Clostridium
perfringens
Coliform
bacteria, E.coli
and
Cryptosporidium
Site
Due for
completion*
Status*
Legal
Instrument
Ashford
Common
3 1 - Ma r - 1 5
D e l a ye d
Notice
Sturt Road,
Haselmere
3 1 - Ma r - 1 6
Ongoing
Notice
T MS
Cryptosporidium
W al t o n
31-Dec-15
Ongoing
Notice
T MS
E.coli
Kangley
Bridge
30-Apr-16
Ongoing
Notice
T MS
Lead
A l l zo n e s
3 1 - Ma r - 2 0
Ongoing
Notice
T MS
Lead
30-Sep-16
Ongoing
Notice
T MS
Lead
31-Dec-16
A MP 6
Notice
T MS
Lead
31-Jul-17
Ongoing
Notice
T MS
Lead
3 1 - Ma r - 1 5
Completed
3 1 - Ma r - 1 5
Undertaking
T MS
Me t a l d e h yd e
3 1 - Ma r - 2 0
O n Ta r g e t
Undertaking
T MS
Me t a l d e h yd e
T MS
Pesticides
Sheafhouse
3 1 - Ma r - 1 5
T MS
Pesticides and
m e t a l d e h yd e
11 treatment
works
3 1 - Ma r - 2 0
T MS
P o we r s u p p l y
Coppermills
3 1 - Ma r - 1 5
Ashton
K e yn e s
Chipping
Campden
Dancers End
Lead in
distribution
Anglian
W at e r b u l k
supply
catchment
Grimsbury
catchment
3 1 - Ma r - 1 5
Completed
3 1 - Ma r - 1 5
Completed
3 1 - Ma r - 1 5
Ongoing
Completed
3 - Ma r - 1 5
Completed
31-Dec-14
Undertaking
Undertaking
Undertaking
Notice
Te l e m e t r y a n d
All sites
31-Dec-14
Notice
alarms
Tu r b i d i t y a n d
T MS
disinfection
B e d w yn
30-Nov-14
D e l a ye d
Notice
control
* D a t e s u s e d a r e t h o s e f o r t h e c o m p l e t i o n o f t h e a g r e e d p r o g r a m m e o f wo r k . Th e r e i s a
further period of 12 months before a programme is officially closed to ascertain the
benefits of the work to consumers.
T MS
Annex 4.1
Delayed programmes
Company
Parameter,
h a z a r d o r d r i ve r
Site
A FW
Ma n g a n e s e
R o yd o n
A FW
Ma n g a n e s e
Blackford
SRN
Bacteriological
Ventor
Reason for dela y
I n i t i a l d e l a ys c a u s e d b y p l a n n i n g
permission issues then subsequent
d e l a ys w e r e e xp e r i e n c e d wi t h m a i n s
cleaning – the company is due to
submit a change application.
I n i t i a l l y d e l a ye d d u e t o d r o u g h t i n 2 0 1 2 .
A d d i t i o n a l d e l a ys e xp e r i e n c e d wi t h
mains cleaning – the company is due to
submit a change application.
P r o t e c t e d s p e c i e s i n s p e c t i o n s e xp e c t e d
to delay scheme by three months.
122
London and South East region
Company
T MS
T MS
Parameter,
h a z a r d o r d r i ve r
Coliform bacteria
and Clostridium
perfringens
Tu r b i d i t y a n d
disinfection
control
Site
Reason for dela y
Ashford
Common
New instrumentation being replaced due
to inappropriate specification.
B e d w yn
Tr e a t m e n t o p t i o n s b e i n g i n ve s t i g a t e d .
Change application will be submitted.
123
Drinking water 2014
Annex 5
Competition in the water industry
The f ollowing table indicates the ext ent of competition in the water
industr y in England and W ales .
Inset appointments in place in 20 14
Sit e
Ris s i n gt on ,
B our t on- o n- t h eW ater
S ho tt o n P ap er ,
S ho tt o n
B ux t ed C h ic k en ,
Fl ix t o n
W yn yar d , ne ar
W olvis t on
B err yf i e lds ,
A yl es b ur y
Br ook l a nds , M i lt o n
K e yn es
G re at Bi l l i ng W a y,
Nor th am pt on
K in gs Cr os s ,
Lo n do n
Lo n g Cr of t R o a d,
Cor b y
O ak ham N or t h,
O ak ham
Pr i ors Ha l l , Cor b y
T he Br i dg e,
Dar tf or d
Me d i a C it y,
S alf ord Q ua ys
Br e wer y S q ua r e ,
Dorc h es t er
Br om le y C om m on,
Br om le y
Em ers o ns G r e e n,
Br is t o l
Far nd o n Ro a d,
Ma rk et
Har b oro u gh
G ra yl i n g we l l,
Ch ic hes t er
G re at W es ter n
P ark , D i dc o t
Ha l e V i l la g e,
T ott en h am
He art of Eas t
G re en wi c h
Ap po int ee
A lb i o n W ater
Inc umb ent and r eg io n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
St atu s
S up p l yi n g
wa ter
A lb i o n W ater
D ŵr C ym r u W els h W ater ,
W ales
Es s ex an d Suf f o lk W ater,
Ce ntr a l a n d E as t er n r e g io n
Nor th um br ia n W ater,
Nor th er n r e g io n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
A ng l i an W ater,
Ce ntr a l a n d E as t er n r e g io n
A ng l i an W ater,
Ce ntr a l a n d E as t er n r e g io n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
A ng l i an W ater,
Ce ntr a l a n d E as t er n r e g io n
S e ver n T ren t W ater, C en tr al
an d E as ter n re g i on
A ng l i an W ater,
Ce ntr a l a n d E as t er n r e g io n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
Un i te d Ut i l it i es , N or th ern
reg i o n
W es s ex W ater ,
W es tern r e gi o n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
Br is t o l W ater , W es tern
reg i o n
S e ver n T ren t W ater, C en tr al
an d E as ter n re g i on
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
P orts m ou th W ater, Lo nd o n
an d S o ut h E as t r e gi o n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
A ng l i an W ater
Har t le p oo l W ater
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
In d ep e nd e nt W ater
Ne t wor k s L td
P ee l W ater
Ne t wor k s L td
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
124
London and South East region
Sit e
Hi l ls Fa r m La n e,
Hors h am , S ur r e y
K en n et Is l an d ,
Re a di n g
K in gs m er e ,
B ic es t er
L la n i li d Par k ,
S ou th W ales
Ma ri n e W har f ,
De ptf ord
Ne w S ou t h
Q u art er, Cr o yd o n
Ne wl a n ds ,
W aterlo o v i l le
Ni n e E lm s ,
Lo n do n
Nor wi c h C om m on,
W ym ondh am
P ark V i e ws ,
E ps om
Ap po int ee
S S E W ater
Ri v ers i de , B ar k i ng
S S E W ater
T he P ort wa y, n e ar
S al is b ur y
Mo D T id wo r t h
ne ar An d o ver
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
S S E W ater
V eo l i a W ater
Pr oj ec ts
Inc umb ent and r eg io n
S ou th er n W ater, L on d on an d
S ou th E as t re g i on
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
D ŵr C ym r u W els h W ater,
W ales
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
P orts m ou th W ater, Lo nd o n
an d S o ut h E as t r e gi o n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
A ng l i an W ater
Ce ntr a l a n d E as t er n r e g io n
S ut to n a nd E as t S urr e y
W ater, Lo n do n a n d S o ut h
E as t re g i on
Es s ex an d Suf f o lk W ater,
Ce ntr a l a n d E as t er n r e g io n
W es s ex W at er,
W es tern r e gi o n
W es s ex W ater,
W es tern r e gi o n
St atu s
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
Inc umb ent and r eg io n
Cam br id g e W ater, Ce n tra l
an d E as ter n re g i on
Es s ex an d Suf f o lk W ater,
Ce ntr a l a n d E as t er n r e g io n
T ham es W ater, L o nd o n a nd
S ou th E as t re g i on
S e ver n T ren t W ater, C en tr al
an d E as ter n re g i on
St atu s
A pp o i ntm en t
gra n te d
A pp o i ntm en t
gra n te d
A pp o i ntm en t
gra n te d
A pp o i ntm en t
gra n te d
W es s ex W ater,
W es tern r e gi o n
A pp o i ntm en t
gra n te d
S up p l yi n g
wa ter
S up p l yi n g
wa ter
S up p l yi n g
wa ter
New inset appointments in 2014
Sit e
Nor ths t o we,
Cam br id g e
W oods M e ad o w.
O u lt o n, S uf f o lk
G re en wi c h
M il l e n ium V i l l ag e
Ca d le y H i l l,
S wa d l inc ot e
Cas t le W a y, O l d
S arum
Ap po int ee
A ng l i an W ater
A ng l i an W ater
In d ep e nd e nt W ater
Ne t wor k s L td
S ou th
St af f or ds h ir e
W ater
S S E W ater
125
Drinking water 2014
Annex 6
Water company indices
Key
Aff init y W ater (AFW )
Albion W ater (ALB)
Independent W ater Net works (IW N)
Portsmouth W ater (PRT)
South East W ater (SEW )
Southern W ater (SRN)
Sutton and East Surr ey W ater (SES)
SSE W ater (SSE)
Thames W ater (TMS)
Industr y aver age (Industr y )
Overall drinking w ater qualit y
126
London and South East region
Process control index
Disinfection index
127
Drinking water 2014
Distribution maint enance index
Reservoir integrit y index
128
London and South East region
Annex 7
Cost recovery
Amount recovered
for checking
sample results
Amount recovered f or
conducting audits,
events and complai nts
£79,254.00
£10,754
£222.00
£0
£135,901.00
£33,744
£45,029.00
£20,862
£8,362. 00
£1,178
£259.00
£0
Dee Valley W ate r
£11,674.00
£4,028
Dŵr Cymru W elsh W ater
£95,534.00
£28,500
Essex and Suff olk Water
£36,001.00
£1,824
£1,813. 00
£2,660
*£592.00
£3,800
£66,970.00
£10,982
£148.00
£0
Portsmouth W ater
£14,467.00
£2,394
Sembcorp Bour nemouth W ater
£15,096.00
£5,738
£220,187.00
£67,564
South East W ater
£80,105.00
£14,212
South Staff ordshire W ater
£25,234.00
£17,556
South W est W ater
£77,182.00
£22,724
Southern W ater
£82,325.00
£38,418
£4,958. 00
£5,510
£14,319.00
£5,586
Thames W ater
£170,681.00
£47,500
United Ut ilit ies
£156,695.00
£43,434
£1,184. 00
£3,800
£73,075.00
£30,780
£133,681.00
£20,976
£1,550, 356.00
£444,524
Company
Aff init y W ater
Albion W ater
Anglian W ater
Bristol W ater
Cambridge W ater
Cholderton and District W ater
Hartlepool W ater
Independent W ater Net works
Northumbr ian W ater
Peel W ater Networks
Severn Trent W ater
SSE W ater
Sutton and East Surr ey W ater
Veolia W ater Projects
W essex W ater
Yorkshire W ater
Total
* IW N p a i d t h e p u b l i s h e d e s t i m a t e d c h a r g e o f £ 2 , 2 9 4 f o r 2 0 1 3 / 1 4 , t h e f i n a l ye a r e n d
c h a r g e f o r 2 0 1 3 / 1 4 wa s £ 8 2 0 ( m a d e u p o f £ 5 9 2 f o r s a m p l i n g a n d £ 2 2 8 f o r e ve n t s ,
c o m p l a i n t a n d a u d i t s ) . I n a c c o r d a n c e wi t h a g r e e d c h a r g i n g p r o c e d u r e s , t h e 2 0 1 4 / 1 5
e s t i m a t e d f e e f o r s a m p l i n g o f £ 5 9 2 w a s t r e a t e d a s p a i d i n a d va n c e , a n d t h e c o m p a n y
r e c e i ve d a r e f u n d o f £ 8 8 2 , b e i n g t h e o ve r p a ym e n t a f t e r t a k i n g i n t o a c c o u n t s a m p l i n g
c h a r g e s f o r b o t h ye a r s a n d t h e a u d i t e ve n t a n d c o m p l a i n t a m o u n t f o r 2 0 1 3 / 1 4 .
129
Drinking water 2014
Annex 8
Glossary and description of standards
These def init ions will assist the understanding of the report where
technical terms have been used.
µg/ l
m ic rogr am pe r l itr e (o ne m il l i on t h of a gram
per l itr e) .
1, 2- D i chl or oet ha ne
is a s o l v en t t ha t m a y b e f o u nd in gro u nd wa t e r i n
th e v ic i n it y of i nd us tr i a l s it es . W here n ec es s ar y
it c an b e rem o ve d b y s pec i a l wa t er tre a tm ent .
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
3μ g/ l a p pl i es .
Ac r yl am id e
E uro p ea n h e al t h - b as e d s ta n dar d . A c h em ic a l
wh ic h is n ot norm a l l y f ou n d i n dr i nk in g wa t er . I t
is pr od uc e d i n th e m a nuf ac t ure of
po l ya c r yl am i d es t h at a re oc c as i o n al l y us e d i n
wa ter t re atm e nt. I ts pr es e nc e i n dr i nk in g wa t er is
l im it e d b y c on tro l of t h e pr od uc t s pec if ic a t io n .
St a nd ar d is 0 . 1µ g/ l.
Ae s th eti c
as s oc i at e d wi t h th e s e ns es of t as t e, s m el l
an d s i g ht .
Ag g re s siv e
a term us e d to in d ic at e th a t t h e wa t er h as a
te n de nc y t o d is s o l v e c op p er ( a nd ot he r m et a ls )
f r om the in n er s urf ac e of a p i pe or wa ter f i tt i ng
s uc h as a ta p .
Al k a li
a s o lu t io n c o nt a i n in g a n ex c es s of f re e h yd ro x yl
i ons , wi t h a p H gr ea te r t ha n s e v e n.
Al u min iu m
oc c urs na tu ra l l y i n s o m e s ourc e wat ers . I t i s
r em ov e d f rom dr i nk in g wat er b y c o n v en t io n a l
wa ter t r e atm e nt (c o a g u la t io n a nd f i l tra t io n) .
A lum i n ium s u l ph a te a n d p ol ya l um i n ium c h l or i de
m a y be us e d as wat er tre atm e nt c h em ic a ls a t
s om e wat er tr e atm en t work s . A n a ti o na l s t a n dar d
of 2 0 0μ g/ l a p pl i es .
Am m oni um
s a lts ar e n at ur a ll y p re s en t i n tr ac e am o un ts i n
m os t wat ers . T he ir pre s enc e m ig ht i n d ic a te
c on t am in at i on of s a n it ar y s i gn if ic a nc e a nd t h e y
i nt erf er e wi t h th e o p er at i on of t he dis i nf ec ti o n
pr oc es s . A n i nd ic at or par am et er wi t h a g u id e
v a lu e of 0. 5m g/ l.
130
London and South East region
An a l yti c al qu al it y co nt ro l
( AQ C)
proc e d ures us e d to en s ure t h at la b ora t or y
an a l ys is m et h ods ar e perf orm in g c orr ec t l y.
An ti mon y
is r ar e l y f o u nd in dr ink i ng wat er .
T rac e am ou nts c a n b e d er i ve d f rom br as s ta p
f itt i n gs an d s o l de rs . A E uro p ea n h e al t h - b as e d
s ta n dar d of 5 μ g/ l a p p li es .
Aq ui fe r
wa ter - c o nt a i ni n g u nd e rgr ou n d s tra t a.
Ar s e ni c
oc c urs na tu ra l l y i n o n l y a f e w s ourc es of
gro u n d wat er. S pec if ic wa ter t re atm e nt is r eq u ire d
to rem o v e it . A Eur o p e an he a lt h - bas e d s ta n d ard
of 1 0μ g /l ap p l ies .
Benz en e
is pr es e n t i n p e tr o l. I t is n ot f o un d i n dr i nk in g
wa ter , b ut it c a n m i gr a te t hr ou g h u nd er gro u n d
p las t ic wa te r p ip es if p etr o l is s p i lt i n t h e v ic i n it y.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of 1 μ g/ l
ap p l ies . S om e bo tt l e d wa ters an d s of t dr i nk s
wh ic h i nc lu d e s o di um be n zo a t e as a n i ngr e d i en t
ha v e b e en r ep ort e d as c o nt a i ni n g b en ze n e .
Benz o(a ) p yr en e
is o ne of s e v er a l c om pou n ds k n o wn as p o l yc yc l i c
arom at ic h yd r oc arb o ns (P A Hs ) . T h ei r s ourc e i n
dr ink i n g wa ter is as a res u l t of de te ri or at i o n of
c oa l t ar, wh ic h m an y y ears ag o wa s us e d t o l i ne
wa ter pi p es . D u e to ex te ns i ve wa ter m ai ns
ref ur b is hm en t a nd r en e wa l i t is n o w r are t o
de t ec t t h is s ubs t anc e i n dr ink i n g wa t er.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
0. 0 1μ g/ l a pp l i es .
Bo ron
i n s urf ac e wa t er s ou rc es c om es f rom i n dus tr i a l
d is c h ar ges or f rom d et erg e nts in tr e at e d s e wag e
ef f lu e nts . T h e v er y l o w c onc e ntr at i o ns f o u n d i n
s om e dr i nk in g wat ers are no t a c o nc ern t o
pu b l ic h ea l th . A Eur o p ea n h e al t h - b as ed s t a n dar d
of 1m g/ l a p p li es .
Br om ate
c an be f orm ed d ur i ng d is i nf ec t io n of dr ink i n g
wa ter t hr o ug h a re ac ti on be t we en n a tur a l l y
oc c ur ri n g br om id e a nd s tr on g ox i d an ts ( us ua l l y
o zo n e). I t m a y b e ge n era t ed in t h e m an uf ac t ure
of s o d i um h yp o c hl or i te d is i nf ec t a nt .
Ex c ep t io n a ll y, gr o un d wa ter c an b e c o n tam in at e d
wi t h brom at e , r e le as e d f rom a n i n dus tr i al s it e.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
10 μg / l a pp l i es .
Bul k su ppl y
wa ter s up p l ie d i n b u lk , us u al l y i n tr e at e d f or m ,
f rom on e wa te r c om pa n y to an ot h er.
131
Drinking water 2014
Cad mi um
is r ar e l y d et ec t e d i n dr i nk in g wa t er a nd tr ac e
am oun ts ar e us ua l l y d ue t o d is s o lu t io n of
im pur it i es f r om pl um bi ng f i tt i ngs . A Eur o p ea n
he a lt h- b as e d s t an d ard of 5 μ g/ l a p p li es .
Cat ch me nt
wh e n us e d i n c o n nec t i on wi th wa ter , th e
c atc hm ent is th e ar e a dra i n ed b y a r i v er or
wa ter bo d y.
Chlo r am in at i on
th e pr oc es s of g e ner a t i ng a c hl or am in e
d is i nf ec ta n t r es id u a l i n wa t er l ea v i n g a
tr e atm e nt work s .
Chlo r am in e
a s u bs t anc e f orm ed b y a re ac ti o n b et we e n
c h lor i n e an d am m oni a, us e d as a d is inf ec t an t i n
d is tr i bu t io n s ys t em s b ec a us e of its lo n g - las t i ng
pr o p ert i es c om par e d t o c h lor i n e.
Chlo r id e
is a c om po n en t of c om m on s a l t. I t m a y oc c ur i n
wa ter na tu ra l l y, bu t i t m a y als o b e pr es en t d ue
to loc a l us e of d e - ic i n g s a lt or s al i n e i ntr us i on .
A n i nd ic at or p ar am ete r wit h a g u i de v al u e
of 2 5 0m g/l .
Chlo r in e r es idu al
th e s m a ll am oun t of c h l ori n e or c h l or am in es
pr es e nt in dri nk i ng wa ter t o m a in t ai n i ts q ua l it y
as i t pas s es t hro u g h t he wa ter c om p an y’ s
ne t work of p i pes a n d h ous e ho l d p l um bi ng .
Ch rom ium
is n ot pr es e nt i n dr i nk i ng wa ter . A Eur o pe a n
he a lt h- b as e d s t an d ard of 5 0 μ g/ l a pp l i es .
Clo st ri diu m p e rf rin ge ns
is a s p or e - f orm in g b ac ter i um th at is pr es e n t i n
th e g ut of wa rm - bl oo d ed an im als . T h e s p or e s c a n
s ur v i ve d is i nf ec ti o n. T he pres e nc e of s p or es i n
dr ink i n g wa ter in d ic at e s h is tor ic c o nt am in a ti o n
th at r eq u ir es i n ves t ig a ti o n. T he s t a nd ar d is
0 p er 10 0m l.
Coa gul at ion
a pr oc es s em p lo ye d d ur in g dr i n k in g wa t er
tr e atm e nt t o as s is t wi t h th e rem o va l of
par t ic u l a te m att er.
Col ifo rm b act e ri a
ar e wi d e l y d is tr i bu t ed i n th e e n v iro nm en t of t en
as a r es u lt of h um an o r a n im al ac t i vi t y, bu t s om e
gr o w o n p l an t m at ter . T hei r pres e nc e i n a w at er
s up p l y i n dic a tes a ne e d to in v es ti g at e t he
i nt egr i t y of t h e wa t er s up p l y s ys t em .
T he s ta n dar d is 0 pe r 10 0m l.
132
London and South East region
Colo n y c ount s
are ge n era l t ec hn i q ue s f or d et ec t i ng a wi d e
ran g e of bac t eri a , th e t yp e s a nd num bers be i ng
de p en d en t o n th e c o n d it i ons of t he t es t .
T hes e c o u nts , if d on e reg u l ar l y, c a n h e lp t o
i nf orm wa ter m an ag em en t, bu t th e y h a v e no
d irec t h ea l th s ig n if ic a nc e . T h e s t an d ard is ‘ no
ab n orm al c h a ng e ’.
Colo ur
oc c urs na tu ra l l y i n u p l an d wat er s o urc es .
It is r em ov ed b y c on v e nt i on a l wa t er tr ea tm en t.
A n at i on a l s t an d a r d of 2 0m g/ l on t h e
P la t in um /C ob a lt ( Pt /C o) s c a le ap p l ies .
Com mun ic at ion pip e
th e c o nn ec ti o n f r om th e wa t er m ai n t o th e
c ons um er’s pro p ert y b ou n da r y.
Comp li an c e a ss e ss m ent
a c om par is on m ad e b y t he I ns pec t ora te of d a ta
ga t her e d b y wa t er c om pa n i es ag a i n s t s t a nd ar ds
an d o th er re g u la to r y r eq u ir em ents .
Comp ound
a c om po un d c o ns is ts of t wo or m ore e l em en ts
i n c hem ic a l c om bi na t i on .
Con ce s sio na r y sup pl ie s
h is t or ic a l f re e s up p l i e s of wa t er f or a
ho us eh o l der , es ta b l is h ed wh en a c om pa n y
wa nt e d to la y m a i ns a c ros s l an d a n d th e
l an d o wne r m ig h t agr e e , s ubj ec t t o a p erm is s i on ,
to t ak e a s u pp l y of wa t er f r om th e m ai n .
Condu ct iv it y
is a n o n - s p ec if ic m eas ure of t he am oun t of
na t ura l d is s o l ve d i n or ga n ic s u bs t a nc es in
s ourc e wat ers . A n i nd i c at or p ar am eter wi th
a g ui d e v a lu e of 2, 5 0 0 µS /c m .
Cont ac t t an k
a ta nk , norm a l l y s it u at ed on a tr e atm en t wo r k s
s it e , wh ic h f orm s p ar t of t h e d is i nf ec t io n pr o c es s .
A d is inf ec t a nt c h em ic a l ( n orm al l y c h l or in e) is
dos e d i nt o t he wat er a s i t f lo ws i nt o t he t a nk .
T he pe ri o d of t im e th a t t h e wa t er tak es t o f lo w
thr o ug h t he t a nk a l lo w s s uf f ic i en t ‘c on t ac t ’ t i m e
f or t h e c hem ic a l to k il l , or d eac t i va te , a n y
v ir us es o r pa t ho g en ic org a n is m s th at m a y b e
pres e nt in t h e wa t er.
Copp e r
i n dr ink i n g wa ter c om es m os tl y f r om c o pp er
p ip es a nd f i tt i n gs in h ous e ho l ds . I n g e ner a l,
wa ter s ourc es ar e n ot ag gr es s i ve t o war ds
c op p er, b u t pr ob l em s v er y oc c as i o n al l y oc c u r o n
ne w h ous i n g es t at es . T hes e ‘b l u e wa ter ’ e ve nts
c an be a v o i de d b y g o o d p lum b in g pr ac t ic es .
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
2m g/l ap p l ies .
133
Drinking water 2014
Cr ypt osp or id ium
is a p ar as it e th a t c aus es s e v ere g as tro e nt er i tis
an d c a n s ur v i v e d is inf ec t i on . It is r em ov e d f r om
wa ter b y c on v e nt i o na l proc es s es f o r r em ov i n g
par t ic u l a te m ater i a l, a nd is i nac t i va t ed b y
u ltr a v io l et l ig ht . I n th e U K, c on t in u ous m on i t or in g
is u nd er tak e n at work s c l as s if i e d b y th e c om pa n y
as b ei n g at s ig n if ic a nt ris k .
C yan id e
is n ot pr es e nt i n dr i nk i ng wa ter . A Eur o pe a n
he a lt h- b as e d s t an d ard of 5 0 μ g/ l a pp l i es .
De ad l eg
r ef ers t o a p i ec e of p i p in g wh ic h is s t o p pe d of f at
on e e n d, b ut is c o nn ec te d t o t h e s u pp l y a t t h e
ot h er en d a n d c a n r es u lt i n s t ag n an t wa t er i n
th e p i pe wo rk .
Di st rib utio n s yst em s
a wa t er c om pa n y’s ne t work of m a ins , p i pes ,
pum p in g s t at i ons an d s er v ic e r es er v o irs t hro ug h
wh ic h tre a te d wat er is c on v e ye d t o c o ns um ers .
Dr in kin g W at er D i re c t iv e
Co u nc i l D ir ec t i v e 9 8/ 8 3/ E C Dec em ber 1 9 98 –
s et t in g o ut dr i nk i ng wa ter s t a nd ar ds to be
ap p l ie d i n m em ber s t a tes .
Dr in kin g w at e r st a nd ar ds
th e pr es c r ib e d c o nc e n tra t io ns or va l u es l is t e d
i n r eg u l at i ons .
Enfo r c em ent a ct ion
th e m ea ns , as s et ou t i n th e W ater Ac t 1 9 89
an d c o ns ol i d at e d i nt o th e W ater I n dus tr y Ac t
19 9 1, b y wh i c h th e S e c ret ar y of S ta te r eq u ir es
a wa t er c om pa n y to c o m pl y wi t h c e rt a in
r eg u l at or y re q uir em en t s .
Ent e ro co cc i
s ee Es c h er ic h ia c o l i .
Env i ro nm ent Ag en c y
th e E n v ir onm en t A g en c y is r es p o ns ib l e f or
m aint a i n in g a nd im pro v i ng t h e qu a l it y of f r es h,
m arin e, s urf ac e an d u nd er gr ou n d wa t er i n
E ng l a nd . Na t ura l R es o urc es W ales i s t h e
eq u i v al e nt b o d y i n W ales .
Ep ic hlo ro h yd r in
c an be f o un d i n tr ac e am oun ts i n p o l yam i ne
wa ter t re atm e nt c h em ic a ls . Its pres e nc e i n
dr ink i n g wa ter is l im it e d b y c o ntr o l of t h e pr o duc t
s pec if ic a t io n. A E ur op ea n h e al t h - b as ed s t a n dar d
of 0 . 1μ g/ l a pp l i es .
Ep id em iolo g y
a pr oc es s of s t ud yi n g th e d is tr i b ut i on of c as es of
d is e as e wi t hi n a p o p ul at i on in r e la t io n t o
ex p os ur e t o p os s i bl e s ourc es of th e i nf ec t io n ,
wi t h a v i e w t o es ta b l is h in g t he ac t ua l s o urc e of
th e i nf ec ti o n.
134
London and South East region
E sc he ri ch i a col i an d
Ent e ro co cc i
are bac te ri a pr es en t i n t he gu t of warm - b lo o d ed
an im a ls . T h e y s h o ul d no t b e pr es e n t i n dr ink i ng
wa ter an d, if p res e nt , i m m edia t e ac t i on is
req u ir ed t o i d en t if y a n d r em ov e a n y s o urc e o f
f aec al c on tam i na t io n t ha t is f o un d. T he s t a n dar d
is 0 p er 1 0 0m l.
Ev e nt
wa ter c om pan i es h a v e t o i nf orm th e I ns p ec to rat e
ab o ut oc c as i ons wh en wa ter qu a l it y or
s uf f ic i e nc y is af f ec t e d or wh e n p ub l ic c o nf i d e nc e
i n dr ink i n g wa ter qu a l i t y m a y b e im pac t e d. T he
Ins p ec t ora t e r ef er t o t hes e i ns ta nc es as ‘ E v en ts ’.
Filt r ati on
wh er e wa t er is p as s e d t hro u gh a p oro us m at er ia l
(e. g. s an d) t o r em ov e s us p e nd e d p art ic u la te
m atter .
Fluo ri de
oc c urs na tu ra l l y i n m a n y wa t er s ou rc es ,
es p ec i al l y g ro u nd wa t e r. It c a n no t b e r em ov e d b y
c on v e nt i on a l wa t er tr e atm en t s o h i gh le v e l s m us t
be r ed uc ed b y b le n di n g wi t h a no th er lo w f lu o ri de
wa ter s ourc e . S om e wat er c om pa n ies are
req u ir ed b y th e l oc a l h ea l th au th or i t y to
f lu or id at e wat er s u p p li es as a pr ot ec ti o n a ga i ns t
to ot h d ec a y. T he dr i nk i ng wat er s t a nd ar d
ens ur es l e v els are s af e i n e it h er c irc um s tan c e.
Fl uo ri d at i on of wat er i s a D e par tm ent of H ea lt h
po l ic y. A E ur o pe a n he a lt h - b as e d s ta n dar d of
1. 5m g/ l ap p l i es .
G eo sm in
a s u bs t anc e pr o duc e d b y a v ar i et y of n at ur al l y
oc c ur ri n g m ic r ob es , n orm al l y i n s urf ac e wat ers
wh ic h g i ves r is e to a c har ac ter is t ic ‘ ear t h y’ o r
‘m us t y’ tas te or o do ur .
G r anu la r a ct iv at ed c a rbon
an ads or be n t f i l tra t io n m edi um us ed t o rem o v e
trac e or g an ic c om po u n ds f rom wat er .
G ro s s alp ha /g ro ss b e t a
rad i o ac t i v it y i n r a w wa ter c a n or i g in a te f rom
na t ura l s u bs ta nc es or f r om a s p ec if ic p o i nt
em is s i o n. W ater c om pan i es ar e r e qu ir e d to
s c ree n f or r a d io n uc li d es th a t em it e it h er a lp ha or
be t a par t ic les . If s uc h s c ree n i ng ex c e e d s gu i de
v a lu es ( gr os s a l ph a 0 . 1 Bq / l, gr os s b et a 1 .0 B q/ l)
th e n f u l l er a na l ys is f or s p ec if ic ra d i on uc l id e s is
c arr ie d o ut t o d et erm i ne t h e or i gi n .
G rou ndw at er
wa ter f rom a q uif ers or o th er u n der gr o un d
s ourc es .
135
Drinking water 2014
H yd ro ge n Ion
(pH)
g i ves a n i n d ic a t io n of th e d egr e e of ac id i t y o f th e
wa ter . A pH of 7 is n e utr a l; va l u es b el o w 7 a re
ac id ic a n d v a lu es a b o v e 7 ar e a lk al i n e.
A l o w pH wat er m a y re s u lt i n p i pe c orros i o n.
T his is c orr ec te d b y a dd i n g an alk a l i d ur in g
wa ter t re atm e nt. A s p e c if ic at i o n of b e t wee n
6. 5 a nd 9. 5 a pp l i es .
Imp rov em ent pr og ra mm es
wa ter c om pan y im pr o v em ent work s , th es e ar e
l eg a l l y b in d i ng o n t he c om pan y a n d e ac h
pr o gr am m e wi l l r em ed y a n ac tu a l or p ot e nt i a l
br e ac h of a dr ink i n g w at er s t an d ard wi th i n a
s pec if ie d t im e p er i od .
Indi c ato r or ga ni sm
an org a n is m wh ic h i nd ic at es th e pr es enc e of
c on t am in at i on a n d h en c e th e p os s ib l e pr es en c e
of p a th o ge ns .
Indi c ato r pa r am et er
s om eth i n g t h at is m ea s ure d t o c h ec k th a t
c on tr ol m eas ur es , s uc h as wa t er tr ea tm ent ,
ar e work i ng ef f ec t i ve l y.
Info rm at ion Le t t e r
f orm al gu i d anc e t o wa t er c om pa n ies g i v e n
b y th e I ns p ec tor at e a n d p ub l is he d o n th e
Ins p ec t ora t e ’s we bs it e a t ht tp :/ / ww w. d wi .g o v .uk
Ins pe cto r at e
T he Dr ink i ng W ater I n s pec t ora te .
Iro n
is pr es e n t n at ura l l y i n m an y wa t er s o urc es .
It is r em ov ed b y wa te r tr ea tm en t. S om e ir on
c om pou n ds ar e us ed a s wat er tr ea tm ent
c hem ic a ls . H o we v er, t he c om m ones t s o u rc e
of iro n i n dr i nk in g wa t er is c orr os i on of ir o n
wa ter m ai ns . A n at i on a l s ta n dar d of
20 0μ g /l ap p l ies .
Le ad
v er y oc c as i o n al l y oc c u rs n at ur a l l y i n r a w wa t ers ,
bu t t he us u a l r e as o n f or i ts pr es e nc e i n dr in k ing
wa ter is p l um bin g in o l der pro p ert i es . If th e wa ter
s up p l y h as a t en d enc y t o d is s o l v e l e ad t h en
wa ter c om pan i es tr ea t t he wa ter t o re d uc e
c ons um er ex p os ur e. T he perm an e nt r em ed y is
f or h o us e h o ld ers t o r e m ove l e a d p ip es a nd
f itt i n gs . T he Eur o pe a n h e al t h - b as ed s t a nd ar d is
10 μg / l.
3
m /d
c ub ic m etr es per da y.
M angan es e
is pr es e n t n at ura l l y i n m an y s o urc es a nd is
us u a l l y r em ov e d d ur in g tre a tm ent . A n at i o na l
s ta n dar d of 5 0 μ g/ l a pp l ies .
136
London and South East region
M ean z on a l com pl ia n ce
pe rc ent ag e
a m eas ur e of c om pl ia n c e wi t h dr i nk in g wa t er
s ta n dar ds i n tro d uc e d b y th e I ns p ec to r at e in
20 0 4.
M ercu r y
is n ot f o un d i n s o urc e s of dr ink i n g wa t er.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
1μ g/ l a p pl i es .
M ethyli so bo rn eol ( M IB)
a n at ura l s ubs ta nc e pr od uc ed b y th e gr o wt h of
a lg a e, n orm al l y i n s urf ac e wa ters wh ic h g i ve s
ris e to a c har ac ter is t ic ‘ e art h y’ or ‘m us t y’ t as te or
od o ur. I t is d et ec te d b y t h e m eth o d f o r as s e s s i ng
tas te an d o do ur .
mg/ l
m ill i gr am per li tr e ( o n e th o us a n dt h of a gr a m
per l itr e).
M icrob iol ogi c al
as s oc i at e d wi t h th e s t ud y of m ic ro bes .
M l/d
m ega l itr e p er d a y ( o ne M l /d is eq u i v a le nt t o
3
1, 0 00 m /d , 1 m i l li o n l i tres /d or to 22 0, 0 00
ga l l ons / d).
Ni ck e l
oc c urs na tu ra l l y i n s o m e gro u nd wa t er a nd wher e
nec es s ar y s p ec ia l tr e a tm ent c a n b e i ns t a l le d t o
rem ov e i t. An ot h er s o u rc e of nic k e l i n dr i nk in g
wa ter is th e c o at i n gs o n m od er n ta ps a n d ot h er
p lum b in g f it t in gs . A E u rop e a n he a lt h - b as e d
s ta n dar d of 2 0 μ g/ l a pp l ies .
Nit r ate
oc c urs na tu ra l l y i n a l l s ourc e wat ers a l th o ug h
h ig h er c o nc e ntr a ti o ns te n d to oc c ur wh ere
f ert il is ers ar e us e d on th e l a nd . N itr at e c a n b e
rem ov e d b y i o n ex c h a ng e wat er tr ea tm en t or
thr o ug h b l en d i ng wi th ot h er l o w n i tra t e s ou rc es .
A E ur op e a n he a lt h - b a s ed s t a nd ar d of
50m g/ l a p p li es .
Nit rit e
is s om et im es p ro d uc e d as a b y - pr od uc t wh e n
c h lor am in e is us e d as th e es s en t ia l r es i d ua l
d is i nf ec ta n t i n a p ub l ic w at er s u pp l y.
Ch l or am ine is th e res i du a l d is inf ec t an t of c h o ic e
i n l arg e d is tri b ut i o ns s ys t em s b ec a us e i t is m ore
s ta b le an d l o ng - l as t i n g. C ar ef u l o per at i o n of t he
d is i nf ec t io n pr oc es s e ns ur es l e v e ls of ni tr it e ar e
k ept b e lo w th e s t an d ar d. A E uro p ea n h e a lt hbas e d s ta n da rd of 0 .5 m g/l a pp l i es .
Noti c e
an ins tr uc t i on s er ve d b y th e S ec r et ar y of S t at e
(i n th e c as e of wa ter s up p l ies , t he C h ief
Ins p ec t or of W ater) re qu ir i n g s pec if ic ac t i on s t o
be t ak en b y th e r ec i p i en t wi t h in a s pec if ie d
tim es c a l e.
137
Drinking water 2014
NT U
ne p he l om etr ic tu rb i d it y u n i t – t h e u ni t of
m eas ur em ent f or t urb i d it y i n wat er
O dou r
c an aris e as a c ons e q ue nc e of na tu ra l pr oc e s s es
i n s urf ac e wa t ers , p ar t ic ul ar l y b et we e n l at e
s pr in g a n d ear l y a u tu m n. W ater tr e atm en t w it h
ac t i v at e d c ar bo n or o z on e wi l l r em ov e n at ur a l
s ubs t anc es c a us in g t a s te . T h e s ta n da rd r el a tes
to t h e e va l u at i ons of a p a ne l of p eo p le as s es s i ng
s am pl es i n th e l a bo ra t or y.
O fw at
th e wa t er i n dus tr y’ s ec on om ic r e gu l at or .
O oc ys t
th e r es is t a nt f orm i n w h ic h Cry pt os p ori d i um
oc c urs in t h e e n v ir o nm en t, an d wh ic h is c ap a b le
of c a us i ng inf ec t io n .
O rg ano l ept i c
c har ac ter is t ic s of a s u bs t a nc e as de tec t ed b y o u r
s ens es , f or ex am pl e t a s te , o do ur or c o l o ur.
O z one p ro ce s s ( oz on at i on)
th e a pp l ic at i on of o zo ne gas in d ri nk i ng
wa ter t re atm e nt.
P ar am et e rs
th e s u bs t a nc es , or ga n i s m s and p ro p ert i es l is te d
i n Sc he d u le 2 an d R eg u la t io n 3 of th e
r eg u l at i ons . P ar am ete r d ef i n it i o ns c an be f o un d
i n th is g l os s a r y.
P athog en
an org a n is m wh ic h c a n i nf ec t hum ans an d
c aus e d is eas e .
PC V
s ee ‘ Pres c r i b ed c onc e ntr at i o n or v a l ue ’ .
P er iod i c rev iew
th e ec on om ic r e gu l at o r’s pr oc es s of s e tt i n g
wa ter pr ic es .
P est i cid e s
an y f u ng ic i de , h er bic i d e, ins ec t ic i de or r e la t e d
pr o d uc t ( ex c l u d in g m ed ic i n es ) us ed f or t he
c on tr ol of p es ts or d is eas es .
P est i cid e s – or gan oc hlo r in e
com poun ds ( ald ri n, d ie ld rin ,
hept a chl or , he pt a ch l or
epo xi de)
ar e no lo n ger us e d i n t he U K b ec a us e t h e y ar e
pers is te n t i n th e e n v ir onm en t. T h e y ar e no t f ou n d
i n dr ink i n g wa ter . A E uro p e an c h em ic a l s t a n dar d
of 0 . 03 μg / l f or e ac h c o m poun d a p p li es .
138
London and South East region
P est i cid e s – ot h er t h an
org ano ch lo ri ne c omp ound s
is a d i v ers e an d l ar g e gro u p of org a n ic
c om pou n ds us ed as w ee d k il l ers , ins ec tic i d e s
an d f un g ic id es . M an y wa ter s ourc es c o nt a i n
trac es of on e or m ore pes t ic id es as a r es u l t of
bo t h agr ic u lt ur a l a nd n on - a gr ic u l tu ra l us es ,
m ain l y o n c r o ps an d f o r wee d c o nt ro l o n
h ig h wa ys a n d i n g ard e ns . W here n ee d ed , wa ter
c om pan i es h a v e i ns t a l l ed wat er tr e atm en t
(ac t i v at e d c ar bo n a n d o zo n e) s o t ha t p es t ic i des
are no t f o u n d i n dr ink i ng wa ter . W ater c om p an i es
m us t t es t f or th os e p e s ti c i d es us e d wi de l y i n
th e ir ar ea of s u p pl y. P es t ic i de m on it or in g t h us
v ar ies ac c or d in g t o r is k . A E ur op e an c hem ic a l
s ta n dar d of 0. 1 μ g /l f or e ac h i nd i v i du a l s u bs t anc e
an d 0 .5 μg / l f o r t h e t ot a l of a l l p es t ic i des ap p l ies .
Pho sp hat e do sin g
tre atm e nt of wa t er th a t r es u l ts i n a pr ot ec ti v e
f ilm b u il d i ng up o n t he i ns i de of p i pes m in im i s i ng
th e l ik e li h oo d of l e ad be i n g pr es e nt in dr ink i ng
wa ter s up p l ie d t hr ou g h l ea d p i pes .
Pl umb oso lv e nc y
th e t en d enc y f or l e ad t o d is s o l v e i n wa t er.
Po l yc yc li c a ro mat i c
h yd ro c ar bon s
(P AH s )
is a gr o up nam e f or s e v era l s u bs ta nc es pr es en t
i n pe tr ol e um - bas ed pr od uc ts s uc h as c oa l t a r.
(s ee B en zo ( a)p yr e n e l i s te d a bo v e f or m or e
i nf orm at io n) . A E ur op e an he a lt h - bas e d
s ta n dar d of 0. 1 μ g /l f or t he s um of a l l th e
s ubs t anc es a pp l i es .
Pow de r ed a ct iv at ed c ar bon
(P AC )
po wd er e d ac t i v at e d c a rbo n is em pl o ye d i n
tre atm e nt pr oc es s es t o r em ov e p o l lu ta n ts .
P re s c rib ed c onc en t r a t ion o r
v alu e ( P C V)
th e n um eric a l v a lu e as s i gn e d to d ri nk i ng wat er
s ta n dar ds d ef i n in g t he m ax im al or m in im al le ga l
c onc e ntr at i o n or v a l ue of a p aram et er .
P riv ate s upp l y
wa ter s up p l ie d f or h u m an c o ns um pti o n or f o od
pro d uc t i o n wh ic h is n o t pro v i d ed b y a wa t er
un d ert ak er or l ic e ns e d wat er s u pp l i er.
P rotoz oan p a ra si t e s
a s i ng l e c e l l or ga n is m th at c an o n l y s ur v i v e b y
i nf ec t i ng a hos t, f or ex am pl e Cry p t os p or i di u m .
Pub li c su ppl y
wa ter s up p l ie d b y a c o m pan y l ic ens e d f or
th at pur p os e .
Raw w at e r
wa ter pr ior t o rec e i v in g tre a tm ent f or t he p ur pos e
of dr i nk i ng .
139
Drinking water 2014
Reg ul ati on s
T he W ater S u pp l y (W ater Q ua l it y) Re g ul a ti o n s
20 0 0 ( E n gl a nd ) an d s u bs e q ue n t am en dm ents ,
an d t he W ater S u pp l y (W ater Q u a l it y)
Re g ul a ti o ns 2 01 0 (W ales ).
Re me di al a ct ion
ac t i on t ak en t o im pr o v e a s i tu a ti o n.
Re mot e o pe r at ed v eh ic le
(RO V)
eq u i pm ent f or i ns pec t i ng are as t ha t ar e d if f i c u lt
to ac c es s , f or ex am pl e , i ns i d e ta nk s a n d p ip e s .
Re si du al di si nf e ct ant
th e s m a ll am oun t of c h l ori n e or c h l or am in es
pr es e nt in dri nk i ng wa ter t o m a in t ai n i ts q ua l it y
as i t pas s es t hro u g h t he wa ter c om p an y’ s
ne t work of p i pes a n d h ous e ho l d p l um bi ng .
Ri sk as s es sm ent
a r e v ie w u n der tak e n t o i de n tif y ac tu a l or
po t en t ia l h a za rds t o h um an h ea l th in a wa te r
tr e atm e nt work s a nd a s s oc ia te d s u p pl y s ys t e m .
Pr i ori t is at i on of r is k is b as ed o n c o ns id er at i o n of
l ik el i ho o d a nd c ons e q ue nc e o f t h e r is k oc c u rri ng .
S ec r et ar y of St at e
S ec re t ar y of St at e f or E n vi ro nm en t, Fo o d
an d R ur al Af f airs .
S el en ium
is a n es s en t ia l e l em en t an d a n ec es s a r y d ie t ar y
c om pon e nt . Am ou n ts i n dr ink i n g wa t er ar e
us u a l l y we l l b e l o w t he s ta n dar d. A E ur op e an
he a lt h- b as e d s t an d ard of 1 0 μ g/ l a pp l i es .
S erv ic e co nne ct ion
c on n ec t i on be t we en t h e wa t er c om pa n y's m a i n
to a c ons um er’s p ro p e rt y.
S erv ic e pip e
an y p i p e s u bj ec t to m ai ns wa ter pres s ur e or
s ubj ec t t o m ai ns pres s ure bu t f o r th e c l os in g
of s om e v a l v e.
S erv ic e r e se rv oi r
a wa t er to we r, t ank or ot h er r es er vo ir us e d
f or t h e s tor a ge of tr ea t ed wa ter wi th i n t he
d is tr i bu t io n s ys t em .
Sug ge st ed n o adv e rs e
re sp on se l ev e l ( S N ARL)
a l e ve l of s u bs t a nc e a t wh ic h n o a d v ers e ef f ec ts
wo u ld be a n tic i p at e d.
Sod iu m
is a c om po n en t of c om m on s a l t. I t is pr es en t
i n s ea wa t er a nd brac k i s h gr ou n d wat er .
S om e tr ea tm en t c hem i c a ls c on t ai n s o d ium .
Co nc en tr at i ons in d ri n k ing wat er ar e ex tr em e l y
l o w, bu t s om e wa ter s of te n ers c a n a dd
s i gn if ic a nt am o un ts to dr ink i n g wa ter wh er e t he y
ar e ins t a ll e d i n h om es or f ac t or i es . A na t io n a l
s ta n dar d of 2 00m g/ l a pp l i es .
140
London and South East region
Sp ri ng s
wh er e wa t er na t ura l l y em erg es f rom b e lo w
gro u n d.
Su lph at e
oc c urs na tu ra l l y i n a l l wa ters an d is dif f ic u lt to
rem ov e b y tr e atm en t. A n i nd ic at or p ar am ete r wit h
a g ui d e v a lu e of 2 50m g/ l .
Sup pl y pip e
s ee s er vic e p i p e.
Sup pl y poi nt
a p oi n t ot h er th a n a c o ns um er ’s ta p a ut h or is ed
f or t h e tak i ng of s am p l es f or c om pl ia nc e wi t h
th e R eg u la t io ns .
Su rf ac e w at e r
un tr ea te d wat er f rom ri v ers , im p ou n di n g
res e r vo irs or ot he r s ur f ac e wa t er s o urc e .
T aste
c an aris e as a c ons e q ue nc e of na tu ra l pr oc e s s es
i n s urf ac e wa t ers , p ar t ic ul ar l y b et we e n l at e
s pr in g a n d ear l y a u tu m n. W ater tr e atm en t w it h
ac t i v at e d c ar bo n or o z on e wi l l r em ov e n at ur a l
s ubs t anc es c a us in g t a s te . T h e s ta n da rd r el a tes
to t h e e va l u at i ons of a p a ne l of p eo p le as s es s i ng
s am pl es i n th e l a bo ra t or y.
T echn ic al aud it
th e m ea ns of c h ec k in g t ha t wa t er c om pa n ies are
c om pl yi n g wi th t h ei r s t at ut or y o b l ig a ti o ns .
T etra ch lo ro et h an e an d
T rich lo ro et h en e
are s ol v e nts t h at m a y oc c ur in gro u nd wa t er i n
th e v ic i n it y of i nd us tr i a l s it es . W here n ec es s ar y
th e y ar e r em o ve d b y s pec i a l is t tr e atm en t.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of 10 μg / l
f or t h e s um of b o th s u bs t a nc es a p p li es .
T etra ch lo ro met han e
is a s o l v en t t ha t m a y o c c ur i n gr ou n d wat er in t he
v ic in i t y of in d us tr i a l s i t es . W here n ec es s ar y i t is
rem ov e d b y s p ec i a l is t wa ter t re atm e nt.
A n at i on a l s t an d ar d of 3 μg / l ap p l ies .
T ime of sup pl y
th e m om ent wh en wa t er p as s es f rom th e wa ter
c om pan y’ s pi p e work i n to a c ons um er’s p i p e work .
T otal ind ic at iv e d o se
is a m eas ur e of th e ef f ec t i v e d os e of r a d ia t io n
th e b od y wi l l rec e i ve f rom c ons um pt i on of t h e
wa ter . It is c a lc u l at e d on l y wh e n s c r ee n in g
v a lu es f or gr os s a lp h a or g ros s b e ta (r ad i at i on)
are ex c e e de d . A n i nd i c at or p ar am eter wi th a
gu i d e v a lu e of 0. 1 0m Sv/ ye a r.
T otal o rg an i c c a rb on
rep res e nts t he t o ta l a m ount of or g an ic m att er
pres e nt in wa ter . A n i n d ic a tor par am et er wi t h
a g ui d e v a lu e of ‘ n o a bn orm al c ha n ge ’ .
T oxic olo g y
th e s t ud y of t he h e a lt h ef f ec ts of s u bs t a nc es .
141
Drinking water 2014
T reat ed w at e r
wa ter t re at e d f or us e f or d om es tic pur p os es as
def in e d i n th e R eg u l at i ons .
T riha lo met ha ne s
ar e f orm ed d ur i ng d is i nf ec t i o n of wat er b y a
r eac t io n b e t wee n c h l or i ne a n d n at ur al l y oc c u rri ng
or g a n ic s u bs t anc es . T he ir p ro d uc t i on is
m inim is e d b y g o o d op er a t io n a l pr ac t ic e.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of 10 0 μ g /l
ap p l ies .
T ritiu m
is a ra d i oac t i ve is o to p e of h ydr o ge n .
Dis c h ar ges t o t he e n v i ronm e nt ar e s tr ic t l y
c on tr ol l e d a nd t h ere is a n a ti o na l p ro gr am m e
of m on it or in g s urf ac e wa ters . A n i n d ic a to r
par am et er wi t h a g u id e v a lu e of 1 00 B q/ l .
T urbid it y
is a m ea s ur e of th e c l ou d i nes s of wa t er. At
tr e atm e nt work s , m eas urem e nt is an im port a nt
no n- s p ec if ic wa t er q ua l it y c o n tro l p ar am eter
bec a us e it c a n b e m o n it or ed c on t in u ous l y o n - l in e
an d a l arm s s et t o a l ert o p era to rs to d e ter i or a ti o n
i n r a w wat er q u a li t y or t he ne e d to o p tim is e
wa ter t re atm e nt. A n i n d ic a tor par am et er wi t h a
gu i d e v a lu e of 1NT U . W hen d et ec te d a t th e
c ons um er’s t a p i t c an ar is e f rom d is t ur ba nc e of
s ed im en t wi t h in wa ter m ains . A n at i on a l s t an dar d
of 4 NT U ap p l i es i n th i s c as e.
Ult r av iol et t re at m ent
th e us e of ul tr a v io l et li gh t t o k i l l pa t ho g en ic
m ic roor g an is m s , f or e x am pl e Cry p t os p or i di u m .
Und er ta ki ng s
Le g a ll y- b i nd i n g pr ogr a m m es of work ag re e d
be t we en a wa te r c om pan y a n d t he C h ief
Ins p ec t or of D ri nk i ng W ater t o ad dr es s ac tu a l or
po t en t ia l wat er q u al i t y is s u es , f or c om pl e ti o n
wi t hi n a s p ec if i e d tim e p er io d .
Vi n yl ch lo rid e
m a y be p res e nt i n p l as tic pi p es as a res i d ua l of
th e m an uf ac tu ri n g pr o c es s of po l yv i n yl c hl or i de
( P VC ) wa ter p ip es . I ts pr es enc e i n dr i nk in g wa ter
is c o ntr o l le d b y pr o d u c t s pec if ic a t io n.
A E ur op e a n he a lt h - b a s ed s t a nd ar d of 0. 5 μ g/ l
ap p l ies .
W ate r s upp l y z on e
a pr e- d ef i n ed are a of s up p l y f or es t a b lis h i ng
s am pl i ng f re qu e nc ies , c om pl i anc e wi t h s t an d ards
an d i nf orm at i on t o b e m ade p ub l ic l y a v a il a b l e.
W HO
W orld H e a lt h O r g an is a ti o n .
W hol es om e/w hol e so men e ss
a l eg a l c o nc e p t of wat er q ua l it y wh ic h is d ef i ne d
b y r ef er e nc e t o s t an d a rds a nd o t her
r eq u ir em ents s et o ut i n th e R eg u l at i ons .
142
Looking after water
in your home
1
FOREWORD
CONTENTS
T
RESPONSIBILITY AND APPROVED PRODUCTS
4
HYGIENE AND QUALITY
6
TREATING WATER IN THE HOME
14
DRINKING WATER STORAGE (TANKS OR CISTERNS)
16
STAINING OF FIXTURES AND FITTINGS
19
OUTSIDE YOUR HOME
20
LEAD PIPES
23
PREPARING FOR FREEZING WEATHER
25
APPROVED PLUMBER SCHEMES
25
USEFUL LINKS FOR FURTHER INFORMATION
27
he quality of drinking water in the UK is consistently amongst the best in the
world. Compliance with standards exceeds 99.9% and where improvements
are needed these are taken on by a combination of regulatory and nonregulatory measures. The net effect being billions of pounds invested into driving
improvements to the benefit of all water consumers.
However the industry is aware that it cannot rest on its laurels. There are always
new threats to drinking water supplies as our raw water resources are subject
to discharges from agriculture, from urban areas and from industry. Increasing
populations and variable weather patterns lead to increasing demands for water that
may be less reliable in its availability. Standards are rightly being tightened where
needed to protect the health of the nation and to ensure that confidence in tap water
is maintained.
There are many actions water companies take – from working in the catchment to
reduce pollution loading, to investing in the latest and most innovative treatment
options, ensuring that the system of pipes bring that water to your homes is in good
condition – to make sure that the water that arrives at your property is wholesome
and safe to drink.
However once water leaves these pipes and enters your home there is a job for the
homeowner to do to ensure that when you drink it or cook with it or bathe in it, it is
still of the highest quality.
The water industry has produced this simple guide of household tips to help you
enjoy the quality of tap water once it reaches your home and to answer questions
relating to water and hygiene issues in the home.
This leaflet provides advice to homes connected to the public water supply. In the UK
around 1 million homes are supplied from private supplies and the advice contained
in the leaflet, whilst broadly useful, may not be wholly relevant in these cases.
Jeni Colbourne,
Chief Inspector,
DWI
2
Sue Petch,
Drinking Water Quality
Regulator for Scotland
Colin Clements,
Acting Chief Inspector,
DWI-NI
3
RESPONSIBILITY AND APPROVED PRODUCTS
Responsibility for pipe work
Your home is connected to the water main in the road by a pipe. The majority of
properties have a stop tap in a chamber near the boundary of your property and
the road – usually in the footpath. There may also be a water meter in this chamber.
There should also be an additional stop tap either immediately outside or inside your
property. This is the stop tap that you should use if needed.
Figure 1 – Typical water
supply arrangements
Top tip
wh ere yo ur
• I t is a go od ide a to kn ow
to ch ec k th at it
inter na l st op ta p is an d
en ing it. Th e st op
wo rk s. Tr y clo sing an d op
on th e pip e wo rk
ta p ca n us ua lly be fo un d
in a do wn st airs
un de r th e ki tche n sin k or
or th e ce lla r if
bath ro om or clo ak ro om ,
yo ur prop erty ha s one.
The part of the service pipe which links the water main in the street to the boundary
of your property (often called the communication pipe) belongs to the water company
and is their responsibility to operate and maintain.
The part of the service pipe leading from the boundary of your property to the point
where it enters your home is your or your landlord’s responsibility, as the homeowner,
along with all the internal plumbing.
Any leak in your front garden or under your drive is likely therefore to be your or your
landlord’s responsibility to repair. Water companies may provide some help with
repairs on your part of the service pipe.
Approved products
Whenever you make changes to your plumbing or connect appliances to the water
supply (e.g. washing machines or dishwashers) in the home, you should only use
those which comply with The Water Supply (Water Fittings) Regulations (England,
Wales and Northern Ireland) and The Water Supply (Water Fittings) Byelaws
(Scotland).
Any work on plumbing systems using unsuitable or incorrectly installed products
can affect the quality of your drinking water or result in leaks that could damage your
home.
Top tips
• O ne ea sy way to ch ec k
wh et he r a produc t is
su ita ble is to loo k fo r th
e WRAS Approved
log o on pack ag ing . WRA
S Produc t Approv al
or eq uiv ale nt approv al sc
he me s en su re th at
each produc t ha s be en te
sted in ac co rd an ce
wi th th e approp riate st an
da rd s. In th is
do cume nt such produc ts
are re fe rred to as
“approved”.
• To ma ke su re th at appr
oved produc ts are
ins ta lle d prop er ly, alway
s us e a WaterSafe1
plumb er.
1
4
www.watersafe.org.uk
5
Top tips
• Reg ula rly cle an yo ur ho
us eh old ta ps,
inc luding any at tach ed fix
tu re s or fit tings,
th oroughly us ing a dil ute
ble ach so lut ion
en su ring th at yo u wa sh
ins ide th e sp ou t.
M ak e su re yo u fo llo w ma
nu fact urers
cle an ing ins tr uc tio ns to
en su re yo u do n’t
damage th e ta p.
Figure 2 – WRAS logo
• After cle an ing th e ta p,
ru n th e wate r fo r
a fe w mome nt s to re mo ve
any re ma ini ng
dis inf ec ta nt.
Contacting your water company
• To preven t po ss ible co nt
am in at ion do no t
leave ite ms such as fla nn
els an d dishc lot hs
on th e ta p to dr y an d ne
ve r all ow fo od or
an im als to come int o co nt
ac t wi th ta ps .
On occasion you may need to contact your local water company. You should be able
to find who this is by reference to a recent bill or statement, in the phone book under
Water, or the internet. Section 10 provides useful links.
HYGIENE AND QUALITY
Tap hygiene
It is important that you regularly clean taps that are, or may be, used for drinking
water. Bacteria and other microorganisms occur naturally and are found within our
homes.
Under certain conditions these can grow both on the outside of the tap and inside
the lip of the spout. They are not visible to the naked eye, but the tap can become
contaminated from food or items washed in the sink or basin.
Taste or smells
Customers occasionally report that their tap water has an unusual taste or smell.
There could be several causes of this and the most common are described below. If
you get a sudden or unusual taste or smell to your drinking water please contact your
water company so that they can investigate the problem.
a) Chlorine taste
A chlorine-like smell or taste is often described as being similar to a swimming pool
or bleach.
Chlorine is added continuously during water treatment as a disinfectant to kill
bacteria and other microorganisms. A small amount of chlorine remains in your tap
water. This is to ensure that the quality of the drinking water is maintained through the
pipe network.
Some people are more sensitive than others to the smell or taste of chlorine and may
become aware of occasional changes in chlorine levels in their tap water. This could
be because the water company has been working on the water mains network or is
having to supply you with water from a different water treatment works.
6
7
Flexible hoses can deteriorate over time and release traces of chemicals that
can cause tastes and smells that are particularly noticeable with hot drinks. See
comments on kettles in section b) below.
If you experience these
tastes or smells in your
tap water it may be
that your equipment
has been installed
incorrectly or are
deteriorating.
Top tip
chlor ine unple as an t,
• If yo u fin d th e ta ste of
a jug of ta p wate r
a go od so lut ion is to pu t
tu ra lly re duce
in th e fr idge. Th is wi ll na
e. Co ve r th e
any chlor ine smell or ta st
urs to preven t
jug an d us e wi th in 24 ho
microo rg an ism grow th .
Top tips
• O ne way of ch ec king if
th e ta ste is caus ed
by wa sh ing mach ine or dis
hwashe r ho se s
is to tu rn of f th e va lve s
wh ich co nt ro l
th e flo w of co ld wate r int
o th e mach ine
over night, if th ey are ea
sy to re ach. Th en,
ru n th e ta p wh ich yo u us
e fo r dr ink ing
wate r fo r a sh ort pe rio d
an d ta ste th e
wate r. If th is so lve s th e
ta ste problem ,
exch ange th e ho se (s) fo r
ne w approved
re place me nt s or fit an ap
proved single ch ec k
va lve on th e en d of th e ma
ch ine ho se wh ere
it co nnec ts to th e ho us eh
old pip e wo rk .
Re me mb er to op en th e va
lve ag ain be fo re
us ing yo ur wa sh ing mach
ine or dishwashe r.
• If it do es no t so lve yo ur
problem th en
co nt ac t yo ur loc al wate r
comp any fo r
ad vic e.
b) Antiseptic / TCP taste
An antiseptic / TCP taste or smell is sometimes described as chemical or medicinal.
These tastes are often associated with rubber or plastic materials used throughout
the home, such as tap washers, washing machine and dishwasher hoses or other
flexible hoses.
Connections for dishwashers and washing machines should be made using approved
products and should also include an approved single check valve. This will prevent
water within the flexible hoses, or the dishwasher or washing machine itself, returning
to your drinking water tap or back to the mains supply.
8
Figure 3 – washing machine cold water valves with check valve
9
c) Unusual tastes in hot drinks
If you notice unusual medicinal or plastic tastes only in hot drinks this can often be
due to the seal within the kettle. This is particularly noticeable in new kettles. Tastes
can also be caused by repeatedly boiling water in the kettle.
Top tips
Appearance
e ke tt le is th e
• To co nfirm wh et he r th
t dr ink wi th
problem , tr y ma king a ho
ave or sauc ep an . If
wate r bo ile d in a microw
th en th e caus e is
th e ta ste ha s go ne away
lik ely to be yo ur ke tt le.
Your water can, on rare occasion, appear discoloured. This can include water having
a cloudy or milky appearance, being brown or orange in colour or having a bluegreen colour. The following sections indicate why this may be and suggests steps
you can take to address it:
a) Cloudy (or milky) water
You may find that your drinking water has a cloudy or white
appearance. The most common cause of this is tiny air bubbles. You
can confirm this by running a glass of water and standing it for a few
moments.
amou nt of wate r
nly fill ke tt les wi th th e
•O
te r ta p.
yo u ne ed us ing th e co ld wa
d) Earthy-musty or stale taste or smell
Untreated water may naturally contain microscopic plants (algae) or other organic
matter. Drinking water treatment processes remove most of these but traces of the
harmless materials can remain and give an earthy-musty smell or stale taste to your
water.
If the water clears from the bottom upwards then the cause is trapped
air. Air in drinking water is completely harmless. It can be caused by
internal plumbing, such as faulty taps or by water being warmed.
If you have air in your hot water you may wish to contact your
WaterSafe plumber or GasSafe heating engineer.
These tastes or smells may also
be caused by poor plumbing
design allowing water to remain
in your pipes for longer than
necessary.
Cloudy water due to air can also be caused by a burst water main or when the water
company has been carrying out maintenance work on pipes. If your water contains
air for the first time, has been cloudy for more than a day or your neighbours are also
affected, contact your local water company.
Top tips
• If you have bee n away for t wo wee
ks or
more, the n the qua lity of water in you
r
home may deterio rate. Thi s can lead
to a
sta le tas te or sme ll and in ext reme cas
es
may cause illness . It is adv isable to run
you r
drin king water tap s after pro longed
per iods
of non-us e.
• If you con tin ue to exp erie nce an ear
thymus ty tas te or sme ll, con tac t you r loca
l
water com pany wh o can help iden tify
the
cause.
10
e) Petrol / diesel / solvent taste or smell
This type of taste or smell can be associated with spills of chemicals or fuels (such
as heating oils, petrol or diesel) on the ground near any water pipes (see section 6.2).
If you become aware of a spill, or notice a petrol-like taste or smell to your water,
contact your local water company immediately.
If the water clears from the top
down then this may be caused
by chalky deposits. You should
contact your local water
company.
Top tips
• R un you r tap for a few min ute s and
fill
ano the r gla ss, if it run s clea r the n it
is
mo st like ly due to wa rmi ng in you r inte
rna l
pipe wor k. Pro per ly lag you r cold water
pipe s to pre ven t wa rmi ng.
• C hec k you r sto p tap is full y ope n.
11
b) Brown or orange water
Occasionally you may find that your cold water looks slightly brown or orange. Over
time deposits can build up in water mains for example rusty deposits from old iron
mains. These deposits can be disturbed if there is a sudden change in the direction
or flow in the water main. This can happen for a number of reasons, for example, a
burst on the water main, bringing a water main back into use after repairs, the water
company having to move water from one area to another to cope with changes in
demand or the use of water for firefighting.
c) Blue-green water
Your water company will normally warn you in advance when it is carrying out
planned work on the water mains and there is a risk of discoloured water and they
will advise you of the actions to take.
Sometimes the water can develop a bluegreen tint. This may be associated with
water that has remained in contact with
copper pipes for a long time or poorly
installed plumbing. The blue-green water
will disappear when the tap is run. This
problem should only last for a few days
whilst the protective layer forms.
If you have not been warned and you notice brown water you should run the tap to
see if this helps the water to clear. If the water does not clear after a short time you
should contact your local water
company. If you have brown
deposits in your hot water
you may wish to contact your
WaterSafe plumber or heating
we bs ite s an d so cia l
• C he ck wate r comp any
engineer.
in in yo ur
Top tip
bu rs t ma
me dia to se e if th ere is a
bu rs t is fixed an d
area . If so wa it un til th e
th en flush ta ps .
Brown water may also be
caused by the deterioration of
your storage tank (see Section
4) or the condition of the
service pipe connecting your
house to the water main in the street. If this is the case your neighbours may not be
experiencing the same issues. You may wish to contact your WaterSafe plumber who
can advise you on the next steps to take.
Top tips
• If you have disc olou red water plea
se do
not do any laun dry unt il the water is
clea r
as this may res ult in sta ining. If sta
ining
occ urs kee p the items dam p unt il the
disc olou red water is gone and the n rewa sh
using a wa shing powder.
12
Copper plumbing
Hot water storage or cylinders as well as most household pipes are often made from
copper. In buildings with new plumbing small quantities of copper can dissolve into
the water until a natural protective layer builds up on the inside of the pipes. Usually
this does not cause a problem other than the risk of slight staining, especially with
white baths and sinks.
Top tips
• To prevent this problem always follow the
manufacturer’s instructions including what
products to use with your toilet and use a
WaterSafe plumber for any plumbing work.
Loo block
A poorly installed toilet cistern or a
faulty flush mechanism can sometimes cause blue water as a result of water
containing loo block siphoning back into the plumbing system. This is more likely
after pipework has not been used for some time
or where there has been a problem in the external
network.
If you experience blue or blue-green water contact
your water company immediately for advice and, if
necessary, to arrange an inspection of your plumbing
system.
Temperature
You may experience warm water when you initially turn on the cold tap. Keeping your
drinking water cold is important as it reduces the risk of harmful bacteria or other
microorganisms growing in your plumbing.
In periods of hot weather the water will naturally be warmer. However the warming of
your water may also happen if your cold water pipe runs very close to a hot water or
13
central heating pipe in your home. Mixer taps can also cause this problem. As a result
you may need to run the cold tap for some time until the temperature drops.
Top tip
lag ging arou nd an d
• Ins ta lling ins ulatio n or
come th is problem .
be t we en pip es may over
plumb er.
Co nt ac t yo ur WaterSafe
TREATING WATER IN THE HOME
The quality of tap water in the UK is very high and is routinely monitored by your local
water company to ensure it meets drinking water quality standards. As a result there
is no need to further treat your water. However some people choose to use filters to
remove traces of chlorine or softeners to remove or reduce hardness. The following
sections provide advice on how to using these safely:
Water filters
Water filters can either be connected to the domestic plumbing (plumbed in) or
separate such as jug filters. Some filters also reduce hardness in the water that
can cause scale build up in kettles. With all types of filter, you should follow the
manufacturer’s instructions for installation, maintenance and use.
Jug filters are designed to be small and portable and filter the water into a glass or
plastic container. The water they produce should be treated like any food and used
as soon as possible. Water in jug filters is best stored in a refrigerator and consumed
within 24 hours after which it should be replaced as there will be insufficient chlorine
to prevent growth of bacteria or other microorganisms.
Care should be taken with filter cartridges to ensure that they do not become
damaged or split. If this occurs, tiny beads or small black particles may appear in the
filtered water. If this happens the filter cartridge should be changed immediately.
14
Plumbed in filters are permanently installed in the cold water supply and are
connected to either the existing taps or a dedicated tap. The installation of a
plumbed-in filter must comply with The Water Supply (Water Fittings) Regulations
and Byelaws. Filters only last for a limited time and should be regularly changed as
recommended in the manufacturer’s instructions.
Water softeners
Water hardness comes from naturally occurring calcium and magnesium salts, and
the harder the water, the more of these salts it will contain. Some people living in hard
water areas choose to artificially soften their water to boilers, kettles and other water
heating appliances to prevent the build-up of scale deposits. Softening will also
reduce the amount of detergent required for washing clothes.
The natural salts which cause hard water also give the water a crisp, pleasant and
fresh taste, which is lost when water is softened. Most softeners replace the calcium
and magnesium that causes hardness with sodium.
It is particularly important that artificially
softened water is not used for powdered
milk for babies’ feed. This is because
powdered milk already contains
sufficient sodium, and very young
babies have a limited tolerance to
sodium. Anyone on a sodium-restricted
diet should follow their doctor’s
instructions. In addition, calcium and
magnesium are essential minerals in
our diet.
Top tips
• If you have a water sof tener ins tall
ed, it is
rec ommended that you have a sep ara
te unsof tened ma ins fed tap for drin king
water.
• S ome sof teners req uire you to not
ify you r
loca l water com pany and see k per mis
sion
bef ore ins tall ing . If in doubt con tac t
you r
water com pany.
The water supply to any plumbed-in
softener in domestic premises must
be via a single check valve to prevent backflow into the mains supply.
Further information can be obtained from the Information and Guidance Note
“Installation of Ion Exchange Water Softeners” on the Water Regulations Advisory
Scheme (WRAS) website.
15
How can I find out how hard my water is?
Check with your local water company’s website if you want to know the hardness of
your tap water.
Figure 4 Typical cold
water storage tank
The design, size or
condition of the tank
can have significant
impacts on your water
quality so you should
check the following.
DRINKING WATER STORAGE
(TANKS OR CISTERNS)
Do I have a water storage tank?
Most homes have cold
water taps supplied
directly from the mains
supply which is preferable.
In older houses the kitchen
cold water tap maybe the
only tap connected directly
to the mains. This section
provides advice to help
you if you have a cold
water tank.
If your home has a cold
water storage tanks it is
normally located within
your roof space.
16
Top tip
et he r a ta p is
• If yo u are no t su re wh
su pp ly a qu ick ch ec k
co nnec te d to th e ma ins
er th e ta p ou tle t. If
is to place yo ur th um b ov
all th e wate r wi th
yo u are able to ho ld back
p is fu lly op en th en
yo ur th um b wh en th e ta
ec te d to a ta nk
th e ta p is lik ely to be co nn
t as k a WaterSafe
no t th e ma ins . If in do ub
plumbing
plumb er to ch ec k ou t th e
ar ra ngemen ts fo r yo u.
Is your tank in good condition?
Traditionally tanks were made of galvanised iron and these will rust over time
resulting in rust particles and iron dissolving into the water. This can lead to ‘bits’ in
your drinking water or the water having a brown or yellowish tinge. It can also give
the water a metallic taste. Modern tanks are constructed of plastic and are unlikely
to cause problems provided that they are approved for drinking water use and are
properly installed and maintained.
Does your tank have a close fitting lid?
Ensure your tank has a close-fitting lid of a suitable material that will
not deteriorate or allow microorganisms to grow on it and drip into the
water. The lid prevents debris falling in and polluting the water supply.
It is not uncommon for birds, rodents or insects to find their way into
tanks that are uncovered or only partially covered. This can cause
anything from particles in the water, to unusual tastes and smells and
could even make you ill. Any vents or other openings should also be
screened with fine mesh for the same reason.
17
Is your tank insulated?
Your tank should also be insulated along with the pipes in the roof space to avoid
freezing and bursting in the winter and warming of the stored water during summer,
when the roof space can get very hot.
Does your tank have an overflow?
The tank should have an overflow pipe to warn you about a potential flood and divert
any excess water safely and conspicuously out of the property otherwise it could
flood your home.
If you notice water coming out of the overflow it means your tank is filling too much.
This probably means the ball valve in the tank needs repairing or replacing and you
should contact a WaterSafe plumber straight away.
STAINING OF FIXTURES AND FITTINGS
Pink/red stains
The reddish-pink colour sometimes seen on shower curtains, bath sealant, or around
taps is not caused by the water itself, but by the growth of common bacteria or other
microorganisms. These can thrive in moist, warm environments like those found in
bathrooms. Their presence does not indicate a problem with the quality of the mains
water supply.
The solution to the problem is to wipe down wet surfaces and increase air circulation
by opening a window or fitting an extractor fan to ensure that affected areas are
quickly dried out after use.
Mould
Is your tank adequately supported?
Modern approved tanks should be able to contain water without collapsing or
splitting, provided they are adequately supported.
It is not appropriate to stand a plastic tank directly on the joists of the ceiling because
the weight will not be uniformly distributed. Check that it is standing on a platform,
which is of suitable thickness and constructed from a material that can support its
weight when filled with water to the rim of the tank. The platform should extend a
minimum of 150mm in all directions beyond the edge of the maximum dimensions
of the tank so that no part of it overhangs the support. Check also that the support
is not rotten or distorted due to leakage or condensation. National standards exist to
ensure that tanks are designed and installed correctly. For example British Standard
(BS 4213:2004) states that the minimum support for plastic storage tanks, of a
capacity up to 500 litres should be at least 15mm thick marine plywood to provide a
durable, rigid, flat and level platform beneath the whole of its base.
Top tip
Black or grey staining around
taps in the kitchen, bathroom
or showers, on the grout
between tiles and in washing
machine powder drawers is
quite common. This can also
appear as a thin black film
or jelly like substance from
your tap. It can be caused
by the presence of airborne
mould that can grow in
damp areas. The problem
is made worse if the area
is poorly ventilated, or if
aerosol deodorants or other
sprays (which provide a
food source for the mould)
are used.
Top tips
• Regu lar use of a dilu te bleach solu tion
wil l
help min imi se pro blems. Ma ke sure you
foll ow ma nuf act ure rs clea ning ins tru
ctio ns
to ens ure you don’t cause any dam age
.
• Remo ve any res idue s left by clea nin
g
pro duc ts, soa p, shamp oo, hai rsp ray or
deo dorant s as the y can pro vide a sou
rce of
foo d wh ich enc ourage s gro wth of bac
ter ia
or oth er mic roo rga nisms.
• Ma ke sure aff ected are as are wel
l
ven tilated .
• Repa ir dripping tap s to avo id sta inin
g on
bat hs and bas ins.
ou t wh et he r yo ur
• If yo u are co nc er ne d ab
su pp orte d yo u
st orage ta nk is su ita bly
fe plumb er.
sh ou ld co nt ac t a WaterSa
18
19
OUTSIDE YOUR HOME
Outside taps and hosepipes
A hosepipe connected to an outside tap can present a serious risk to water quality in
the home unless it is protected against backflow to prevent water returning to your
drinking water tap or to the mains supply. In most cases this is easily achieved by
fitting an approved double check valve which should prevent any contaminants being
drawn back into the pipe work.
Top tips
at th e ta p an d ide all y
• Tur n of f th e ho se pip e
t in us e.
fu lly dis co nnec t wh en no
te d wi th a se lf• H os ep ipe s sh ou ld be fit
as a tr igger sp ray
clo sing flo w co nt ro l (such
un at te nded .
gu n) to preven t us e wh en
ne ve r be place d int o
• H os ep ipe ou tle ts sh ou ld
ck et s or wate ringdrain s, ga rden po nd s, bu
submerge d in
ca ns so th at th ey be come
in wate r be ing
wate r as th is may re su lt
dr ink ing wate r
sipho ne d back int o yo ur
su pp ly.
ps or pip ewor k are
• Ens ure any ou tdoo r ta
er.
prop er ly ins ulate d in wi nt
If you become aware of a chemical spill, for
example, if a vehicle leaks a lot of oil or fuel on
your driveway or you have a spillage of heating
oil, remove as much as possible straight away
and inform your water company. If the spillage
is extensive you should also contact your local
authority which may have specialised services to
help you dispose of any waste material.
Once soil and plastic pipes become contaminated
in this way, the only solution is to completely
replace the pipe with either a metal or barrier pipe
system (a plastic pipe with a layer of metal foil for
added protection). This is a job for a WaterSafe
plumber or a member of an approved contractor
scheme who specialises in underground
installations, groundwork or external services.
Water reuse systems
Your house might be connected to an individual or a communal water recycling
system. Individual systems are normally fed by rainwater or by grey water reuse.
A rainwater harvesting system collects rain water from your roof, and a grey water
reuse system collects water from sinks and baths. This water is then saved in a
storage tank and can be used for outside taps or flushing toilets. Communal water
recycling systems may use a variety of sources and do not necessarily feed a storage
tank. Pipes carrying recycled water should be appropriately labelled. It is vital that
these water reuse systems are kept completely separate from your drinking water
supply.
Check your water reuse system from time to time to see if the water in the tank, if it is
accessible, looks murky or starts to smell. If it does contact the manufacturer to get
a professional to check it over and have it cleaned.
Chemical spills on your driveway or garden
You should take care not to spill any chemicals or fuel on the ground. Products such
as heating oil, petrol, diesel and creosote contain chemicals that can rapidly soak
through the driveway or soil and permeate plastic water pipes, causing unpleasant
tastes and smells.
20
If you have any problems with your rainwater harvesting or grey water system, do
not attempt to connect the mains water supply to your toilet’s supply. Always use
a WaterSafe plumber who understands reuse systems and tell them you have a
rainwater or grey water system as they will know how to fix it.
Check your normal plumbing system to make sure the rainwater system is not directly
21
connected to your drinking water. Ensure any mains water back-up goes through an
appropriate, properly installed backflow prevention device.
Make sure the garden tap and pipes carrying rainwater in your house have been
labelled to remind your visitors or tradespeople that this is not regular drinking water.
Don’t remove this labelling, as it is there to keep you and your family safe and to let
your plumber or other workers know the plumbing in your house has a rainwater
harvesting or grey water system.
If you have a rainwater harvesting system and your drinking water tastes odd or
appears cloudy or discoloured, call your water company immediately so that they can
arrange an inspection of your plumbing.
Top tips
te r, ch ec k an d re ad
• If yo u have a wate r me
an inc re as e in th e
it re gu lar ly. If yo u no tic e
be ing re co rded , it
amou nt of wate r th at is
back-u p wate r is
co uld be th at th e ma ins
pe cia lly if th ere ha s
be ing us ed a lot mo re , es
no rm al, bu t it’s
be en no ra in. Th is co uld be
ible, to ma ke su re
wo rt h ch ec king, if ac ce ss
e to a problem wi th
th at th e inc re as e isn’t du
th e ra inwater system ..
no t fill ing , ke ep yo ur
• If yo ur to ile t cis te rn is
a buck et of wate r
to ile ts wo rk ing by us ing
te rn so yo u ca n
to flush th em or fill th e cis
flush it no rm all y.
inf ec tio n un its,
• H ave all filters (or UV dis
d at th e times
if yo u have one), se rv ice
re commen de d.
of leave s, mo ss an d
• K ee ping gu tters cle ar
ater cle aner.
de br is wi ll ke ep th e ra inw
fill yo ur sw immi ng
• Don’t us e ra inwater to
g po ols as yo u ca n’t
po ol or ch ildre n’s padd lin
wi ll no t have
gu aran te e th e ra inwater
ha rmfu l bacter ia in it.
22
LEAD PIPES
Lead is present in our environment and comes from a variety of sources and may be
present in low concentrations in air, food, soil or water. It can build up in the body
and it can be harmful, especially to young children.
Lead can be released into water from lead pipe work, brass water fittings, lead-based
solder or other water fittings containing lead.
Top tip
• Always use a WaterSaf e plum ber.
The y
wil l onl y use app roved mater ials suit
able
for drin king water and never use lead
solder on you r drin king water plum bin
g.
Standards and testing
Water companies take samples from randomly selected customers’ properties to
ensure the water supplied meets high quality standards. If the legal lead standard
is exceeded in a water sample taken from your property then your water company
will contact you to make you aware of the result. Your water company will be able to
advise you on their policy for lead pipe replacement which will include replacement of
the section of pipe owned by the water company free of charge. It is recommended
that customers consider replacing all pipe work in contact with drinking water
including any internal lead plumbing.
How do you know if there are lead pipes in your home?
If your home was built before 1970 it may have lead pipes. If it was built after 1970 it
is unlikely to have lead pipes as their use in drinking water systems became illegal.
Even in properties with no lead pipe work it may be that there are other sources of
lead in drinking water such as brass fittings or improperly used lead based solders.
Each property is different. However it is worth checking behind the cupboards in your
kitchen to look at the incoming pipe work. You may also need to look in other places,
e.g. under the stairs. Find the pipe leading to the kitchen tap. Check along as much
23
of its length as possible to see if it is made of lead. Unpainted lead pipes are dull grey
in colour. They are also soft. If you scrape the surface gently, you will see the shiny,
silver-coloured metal beneath.
earthing purposes even though this has not been allowed for new installations since
1966. Therefore if you alter or replace your lead pipe-work you may need to seek
advice from your electricity supply company or an approved electrical contractor.
PREPARING FOR FREEZING WEATHER
If your home suffers a burst pipe during
periods of cold weather, you could
be left with no water and a hefty bill
to repair the damage to your home.
Safeguard your water supply by
following these simple steps to protect
your home and refer to your water
company’s website for tips and advice.
General advice can be found on-line
on Water UK’s website –
www.water.org.uk/news-water-uk/
latest-news/preparing-winter
Figure 5 – Example lead pipe arrangement
If in doubt, ask a WaterSafe qualified plumber or your local water company for
advice. You can also ask your water company to test the water at your kitchen tap as
lead levels may be low even if there are lead pipes in your property.
Top tips
• I t is a goo d idea to kno w wh ere you
r
inte rna l sto p tap is and to che ck tha
t it
wor ks. Try clos ing and ope ning it. The
sto p
tap can usu ally be fou nd on the pipe
wor k
under the kitchen sink or in a dow nst
airs
bat hro om or cloa kro om , or the cell ar
if
you r pro perty has one .
• If you get a leak or burst pipe inside
the
pro perty you wil l nee d to tur n the inte
rna l
sto p tap off to pre ven t any floo ding
or
dam age .
• Ensu re any outdoo r tap s or pipe wor
k are
pro per ly insu late d in win ter.
What can you do to reduce lead in your water?
If your home has lead pipes there are short term measures you can take to reduce
the amount of lead in your water. Run the tap to remove water that has been standing
in the pipes for long periods, for example, overnight, or if no one has run the taps for
several hours. In these circumstances, draw off a washing-up bowlful of water from
the kitchen tap to clear the water which has been standing in the pipes. This need
not be wasted but can be used on the garden or for something other than drinking or
cooking.
In the long term pipe replacement is the best solution and you should discuss this
with your water company who may be able to coordinate with replacement of their
section of the pipe. Your existing lead supply pipe may have been used for electrical
24
APPROVED PLUMBER SCHEMES
To ensure that any work is done properly it is recommended that you use a
professionally qualified plumber for any plumbing work. When you are looking for a
plumber select a business that is a member of an Approved Contractors’ Scheme,
such asWaterSafe.
WaterSafe is a dedicated online search facility bringing together thousands of
qualified contractors employed by plumbing businesses from seven existing
Approved Contractors’ Schemes across the UK. These schemes aim to raise
plumbing standards by helping customers find the nearest qualified plumbing and
25
heating professionals. To search for a plumbing business near you visit the WaterSafe
website2 and enter your postcode.
Members of Approved Plumbers schemes have a recognised plumbing qualification
and knowledge. They give their customers legally recognised certificates, confirming
that the plumbing work they have carried out complies with The Water Supply (Water
Fittings) Regulations and Byelaws. All members of the WaterSafe Contractors’
Scheme carry agreed levels of Public Liability Insurance and operate a customer
complaints scheme.
To ensure that members continue to provide excellent service, approved
contractor schemes not only investigate any technical complaints from
customers but also regularly audit members’ workmanship to make
certain that it meets the requirements of The Water Supply (Water Fittings)
Regulations and Byelaws.
The seven Approved Contractors’ Schemes that form part of
WaterSafe are:
•T
he “Water Industry Approved Plumbing Scheme” (WIAPS)
administered by WRAS, • “ Aplus” administered by AWG Limited,
• “ TAPS” administered by Thames Water Utilities Limited,
• “ Water Mark” administered by Severn Trent Water Limited,
•W
ater regulation approved contractor or person schemes
administered by SNIPEF Management Limited, the
Association of Plumbing and Heating Contractors
Limited(APHC) and the Chartered Institute of Plumbing and
Heating Engineering (CIPHE).
To contact an Approved Plumber, look on the websites of the
organisation which runs the scheme, or search the WaterSafe
website.
The seven Approved Contractors’ schemes also run specialist
sector schemes for ground workers, underground workers or
external services. These professions are qualified for external
work only such as leakage detection or service pipe repairs and
renewals.
2
26
USEFUL LINKS FOR FURTHER INFORMATION
Water companies
The Water UK website provides links to each water company:
www.water.org.uk/about/our-members
Drinking water regulators
Drinking Water Inspectorate (England & Wales) – www.dwi.gov.uk/
Drinking Water Quality Regulator for Scotland – www.dwqr.org.uk/
Drinking Water Inspectorate (Northern Ireland) – www.doeni.gov.uk/niea/water-home/
drinking_water.htm
Advice on plumbers and The Water Supply (Water Fittings)
Regulations and Byelaws
Water Regulations Advisory Scheme (WRAS) – www.wras.co.uk
Practical advice videos can be found at www.wras.co.uk/consumers/resources/
videos/
To find approved products
Water Regulations Advisory Scheme (WRAS) – www.wras.co.uk/directory
Information on the causes of copper corrosion
Foundation for Water Research – www.fwr.org/copper.pdf
Advice on water filters and softeners can be found at
British Water – www.britishwater.co.uk
UK Water Treatment Association (UKWTA) – www.ukwta.org
Finding a qualified plumber through WaterSafe
WaterSafe – www.watersafe.org.uk
Finding a qualified plumber through Approved Contractors’ Schemes
The “Water Industry Approved Plumbing Scheme” (WIAPS) administered by WRAS:
www.wras.co.uk/consumers/approved_plumber_scheme/
“Aplus” administered by AWG Limited:
www.anglianwater.co.uk/developers/plumbers/sectored-contractors.aspx
www.watersafe.org.uk
27
“TAPS” administered by Thames Water Utilities Limited:
http://secure.thameswater.co.uk/dynamic/cps/rde/xchg/corp/hs.xsl/17380.htm?utm_
source=leafletletter/approvedplumbersutm_medium=print/approvedplumbersutm_
campaign=plumber
“WaterMark” administered by Severn Trent Water Limited:
www.stwater.co.uk/businesses/watermark-plumbers/
The Scottish and Northern Ireland Plumbing Employers Federation (SNIPEF):
www.snipef.org/
Association of Plumbing and Heating Contractors Limited (APHC):
www.aphc.co.uk/
The Chartered Institute of Plumbing and Heating Engineering (CIPHE):
www.ciphe.org.uk/
Information for Landlords
Landlord and Tentant Address Portal (Landlord TAP): www.landlordtap.com
“Landlord TAP is an easy to use website that allows Landlords and Managing Agents,
of properties in England & Wales, to provide water companies with details of those
responsible for the payment of water and/or sewerage charges for their tenanted
properties.”
WWW.WATER.ORG.UK
28
WWW.WRAS.ORG.UK
29
Drinking water
2013
Public water supplies in the
London and South East region of England
July 2014
A report by the Chief Inspector of Drinking Water
Drinking Water Inspectorate | Nobel House, 17 Smith Square | London | SW1P 3JR | Tel: 0300 068 6400
www.dwi.gov.uk