Your guide to
Septic Tank Applications
For residents and installers in Golden Plains Shire
About septic tank permits
Under the Environment Protection Act 1970, any person requires a permit from Council to
construct, install or alter any part of a septic tank system. Legal penalties apply for work carried
out without a permit.
The permit consists of a two stage process:
1. A ‘Permit to Alter/Install’ a septic tank system. This permit must be issued before a
building permit can be issued.
2. A ‘Certificate to Use’ the septic tank system. This permit must be issued before a
building Certificate of Occupancy can be issued.
Contact us
Call Golden Plains Shire Customer Service
Visit our Bannockburn Office
Phone: (03) 5220 7111
Local call: 1300 36 30 36
Fax: (03) 5220 7100
2 Pope Street
Bannockburn Victoria 3331
Postal Address
Visit our Linton Office
Golden Plains Shire Council
PO Box 111
Bannockburn Victoria 3331
[email protected]
68 Sussex Street
Linton Victoria 3360
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Do you need a permit?
When considering whether a Permit to Install or Alter is required, please refer to the following
tables:
Application to install a septic tank system

Installing a new system

Replacement of an existing system

Upgrade of an existing system to a system of a different type, such as:
o
Upgrade from a split system to an all waste system
o
Upgrade from a primary treatment system to a secondary treatment system
Application to alter a septic tank system

Replacement or relocation of one part of an existing system such as:
o
Relocation of absorption trenches
o
Relocation of irrigation lines
o
Upgrade of an effluent disposal area
o
Dwelling extensions where there is an
addition of wastewater generating fixtures,
fittings or appliances
o
Dwelling extensions where the number of
habitable rooms is increased. Habitable rooms
include any room that may be closed off with a
door, such as a study, library or sunroom that
could be used for the purposes of a bedroom.
o
Change of use of a property i.e. from a dwelling
to a shop where installation or replacement of
the system is not required.
i
Note: if during the
application process for an
alteration it is identified that
the alterations required
meet the definitions for an
installation, then the
application will be
considered a new
installation.
You may choose to submit applications directly, or your plumber/drainer may submit an application
on your behalf. Either way remember that you as the owner must sign the application form.
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All septic tank applications (installation and alteration) require the following:
1
Completed and signed application form
2
House/Building Floor Plan (detailing all rooms and plumbing fixtures)
3
Site Plan (refer to Site Plan section of this document)
4
Land Capability Assessment (if applicable – refer to Land Capability Assessment
section of this document)
5
Current copy of Title and Plan of Subdivision
6
A copy of your Planning Permit (if applicable)
7
Applicable fee (refer to application form for current fees)
*Applications cannot be assessed until all documentation is received.
Important reminder:
 Any septic tank system must comply with the EPA Code of Practice and the Australian
Standard for onsite wastewater management
 Any septic tank work must be carried out by a licenced plumber.
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Selecting your septic system
This is a vital decision to ensure the system you select for your property will be sustainable and
suitable for the conditions of the site.
Information on types of systems is available in community fact sheets on Council’s website, on the
Victorian Environment Protection Agency (EPA) website and through discussions with your plumber
and Council’s Environmental Health Unit. Types of systems available are listed on the Victorian EPA
website under ‘onsite wastewater’.
Types of septic systems
The two most common types of systems installed in Golden Plains Shire are:
1. Primary treatment
2. Secondary treatment
This is a conventional septic tank connected to
absorption trenches, usually a gravity based
system.
This is either a septic tank combined with a
sand filter; or a packaged treatment plant.
Both types are commonly connected to
subsurface irrigation lines.
Factors which may determine your decision about which system to use include:
 Restrictive site conditions i.e. heavy clay based soils, proximity to water courses or other
surface water, lot size.
 Cost of installation and ongoing maintenance costs
 Potential to irrigate garden and garden beds with effluent
 Recommendations in a Land Capability Assessment (if applicable)
 Restrictions on your land title relating to onsite wastewater disposal.
Placement of septic systems
Discuss with your plumber the suitable placement of the septic tank system and note that
construction over any part of the system is prohibited.
Factors to consider when weighing up proposed location of the septic tank system include:
 Restrictions on title or planning permits regarding placement of a wastewater system (if
applicable)
 Recommendations from a Land Capability Assessment (if applicable)
 Locations of future sheds, house extensions, swimming pools, tennis courts, dog yards,
clotheslines, garden paths and driveways
 Required fall from the house to the septic tank system (discuss with your plumber)
 Location of internal plumbing and main outlet from the dwelling
 Setbacks to site boundaries, surface water, dams, drainage easements, storm water drains,
services, buildings (refer to setbacks / buffer distances of this document)
 Future landscaping (some systems are able to reuse effluent to irrigate garden beds if
constructed early)
 Septic tanks are installed at ground level so lids, vents, alarms are visible – consider whether
you want to see these components from your lounge room and/or decking area.
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Providing a site plan with your application
The Site Plan provided with your application must be legible and detailed.
Septic tank Site Plans are just as important as your Building Plans - rough sketches with no site
details will not be accepted.
Failure to provide a suitable plan with your application will result in a delay to the processing of your
permit as you will be asked to resubmit.
If your neighbour has a dam on their boundary, or you have a dam or waterway running through
your property, it must be shown on your plan. An appropriate site plan will ensure that everyone
understands the required works and your permit can be issued without delay.
The following details need to be included on your plan:
 Locations and dimensions of all buildings
or proposed buildings

Locations and dimensions of all current
and proposed structures such as
swimming pools, tennis courts, dog yards,
garden paths, driveways, cubby houses,
etc

Water tanks, water pipes, storm water
drains

Driveways

Underground power, water and
telecommunications connections

Sites with hills, an indication of surface
runoff

Location of proposed system including
disposal field

The position and direction of North

The fall of the land

Distances from the closest part of the
septic system to site features including;
property boundaries, buildings, sheds,
other services, waterways, dams and
easements.
i
Note: your Site Plan is
important – a poor plan will
result in delays to the
processing of your permit as
you will be asked
to resubmit a suitable plan.



Plans don’t have to be
professionally drawn
but they do need to
be clear, legible and
detailed.
Your builder needs
detailed plans to build
your house and your
plumber needs
detailed plans to
install a septic tank.
Include as much detail
as possible on your
plan.
On the following page you will find examples of Site Plans:
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Suitable site plan – example 1 – Septic tank and absorption trenches
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Suitable site plan – example 2 – AWTS and subsurface irrigation
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Land Capability Assessments
Do you need a Land Capability Assessment?
If your property/development meets any of the following criteria, a Land Capability Assessment
(LCA) will be required. Is your site:







smaller than 4000 m2 (1 Acre)
within the Moorabool (Sheoaks) Open Potable
Water Catchment Area
classified as high risk for groundwater –
groundwater is of high quality and within 5 metres
of the surface
of a slope of greater than 20%
covered by 50% or more FO (Flood Overlay)
smaller than 2 hectares and a primary treatment
system is proposed in an area where clay based
soils are evident
a non-residential development.
i
Note: in rare circumstances,
there may be an accumulation
of additional constraints that,
upon assessment of an
application by Council,
warrant a LCA.
About Land Capability Assessments (LCA)
LCA’s are to be prepared in accordance with EPA publication 746.1 and the MAV – Victorian Land
Capability Assessment Framework and must be carried out by a suitably qualified consultant (soil
scientist or hydro-geologist).
A LCA will detail the groundwater depth, soil permeability, average rainfall, soil category rating; soil
classification and any other aspects of the site relevant to that particular property. The information
contained in a LCA report will determine a range of recommended irrigation and effluent disposal
designs that are dependent on soil classification.
If a LCA is required for your property, you need to engage an assessor and ask them to contact
Council to discuss the assessment with an Environmental Health Officer prior to commencement.
This will ensure that the assessment addresses any constraints specific to the site. Ensure you
provide the assessor with all the relevant information including future land use plans, such as plans
for house extensions or sheds.


Details of areas in Golden Plains Shire which are classified ‘high risk groundwater’ and
‘heavily sloped’ are detailed in Map 16 of Council’s Domestic Wastewater Management Plan
(available on the website)
If you are unsure if your application requires a LCA, please make sure you contact Council
and speak with an Environmental Health Officer prior to lodging an application.
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Conventional septic tanks
Septic tanks must comply with Australian Standard AS/NZS 1546.1.
Conventional septic tanks are a minimum of 3200 Litres. Wastewater is retained within the tank for
a minimum of 24 hours where solids settle to the bottom of the tank and anaerobic digestion of
organic solids occur. The liquid content is discharged to absorption trenches preferably by gravity, or
by a pump well where sufficient fall cannot be achieved.
Septic tanks are to be de-sludged every three years or as required upon assessment by a suitable
contractor. Septic tanks need to be installed in stable ground and all inspection openings must be at
ground level so that the tank can be located and maintained i.e. inspection openings, inlet of septic
tank and access lids.
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Absorption trenches
Absorption trenches must be constructed in accordance with Australian Standard AS/NZS 1547.
Absorption trenches are a traditional method of disposal of wastewater from primary treatment
septic tank systems. The trenches are constructed with a “slotted pipe” or “arch tunnel” to distribute
the effluent evenly along the trench.
The effluent is disposed of by:
a) absorption into the surrounding soils
b) transpiration into roots of grasses above the trench and
c) evaporation through the top-soil.
Absorption trenches are to be a maximum length of 30 metres, a minimum 2 metres apart, each
installed with a distribution box at the beginning of the trench with access at ground level. The top
of the trench is to be mounded to allow for natural settlement of soil and to stop surface water
entering the trench. Absorption trenches are not suitable in heavy clay based soils.
Construction of trenches are to be in accordance with the following schematic:
Aggregate is to be 20-40mm clean, hard quartz stone or other approved stone free of dust, dirt,
loam, soft particles, organic and other foreign matter.
Trenches are to be installed a maximum of 400mm deep. Deeper trenches will cause the system to
fail. Where sufficient fall cannot be achieved between the septic tank and absorption trenches to
maintain this depth, a pump well will need to be installed prior to the trenches.
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Sand filter systems
Sand filters are a secondary treatment system installed after a conventional septic tank prior to
the effluent disposal system.
Sand filters distribute effluent from a septic tank across a bed of sand. As the effluent passes
through the sand, aerobic oxidation occurs dissolving and suspending the organic matter. This
results in a higher level of treatment to the effluent.
When installing a sand filter system, the sand filter needs to be sized accordingly to the hydraulic
and organic load for the proposed system. The following table provides minimum sand filter sizes.
These have been calculated based on AS/NZS 1547 and the EPA Code of Practice. Without additional
evidence to support the reduction of the size of the sand filter, the size provided in the tables is the
minimum that will be approved within Golden Plains Shire.
Sand Filter Size
Number of
habitable rooms
Sand filter size
1
6 m2
2
9 m2
3
12 m2
4
15 m2
5
18 m2
i
Note: a habitable room
includes any room that may
be closed off with a door,
such as a study, library or
sunroom that could be used
for the purposes of a
Sand filters are to be installed in accordance with EPA certificate of approval 1.3/03 and the
schematic on the following page.
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



Aggregate is to be clean, hard quartz stone or other approved stone free of dust, dirt, loam, soft
particles, organic and other foreign matter.
Small aggregate is to be 5-10mm in size.
Large aggregate is to be 20-25mm in size.
Sand layer is to be clean washed sand that:
o Contains less than 5% clay and fine silt content by volume
o Has an effective size between 0.25 and 0.6mm
o Has a uniformity coefficient less than 4
In addition to the above schematic, the following are requirements of installation of Sand Filter
Systems:





Distribution boxes are to be installed so that the access cover is at ground level
Base of the sand filter is to be lined
Distribution pipes are to be 90mm slotted pipe a maximum 1 metre spacing apart and a
minimum 500mm from the edge of the sand filter
The distribution and/or distribution pipes are to be vented
Pump wells are not to be installed inside the sand filter.
Aerated Wastewater Treatment Systems (AWTS)
AWTSs are a secondary treatment system installed prior to the effluent disposal system.
AWTSs aerate effluent from a septic tank (or primary chamber) using electrically powered blowers.
In addition to aeration, clarification and disinfection is often used to achieve a higher level of
treatment. AWTSs are required to be serviced by a qualified service agent once every quarter and
the report provided to Council. AWTSs are required to be installed in accordance with the relevant
EPA certificate of approval for the system. A list of approved AWTS can be found on the Victorian
EPA website under ‘onsite wastewater’.
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Sub-surface irrigation systems
Sub-surface irrigation disposes of effluent through a network of pressure-compensating pipes and
emitters in the sub-soil (100-150mm below ground level).
Irrigation systems are the preferred effluent disposal method for secondary treated effluent i.e.
effluent which has been treated through either an AWTS or a sand filter system. As there are
different types of pipe available, irrigation pipe is required to be approved for use with waste water.
Irrigation pipe must be purple or lilac in colour. Irrigation systems are to be fitted with a in-line mesh
filter, an air valve and a flush valve as per manufacturer’s specifications. Larger irrigation systems
(generally above 400 m2) should be zoned in accordance with pump capacity. Sub-surface irrigation
can be used in clay based soils in combination with gypsum application and can be used to irrigate
gardens and garden beds. Irrigation systems need to be flushed periodically and the filter cleaned
regularly (normally fortnightly to monthly).
Disposal field sizing
A LCA will determine the size of your disposal field (irrigation area required) in the report.
To assist property owners who are not required to obtain a LCA, the table included in the ‘Sizing of
Effluent Disposal Systems’ section outlines the minimum disposal area for onsite wastewater
disposal. These figures have been calculated based on AS/NZS 1547:2012 and the EPA Code of
Practice. They are based on a clay dominated (Category 6 – DIR/DLR 2 mm/day) soil type and
therefore provide a conservative approach.
The minimum disposal areas provided in the table are a
minimum that will be approved within Golden Plains
Shire Council, unless additional evidence (e.g. a LCA) is
provided to support the reduction of the recommended
area.
Final approval of your effluent disposal area will be
finalised after an assessment of the site and the
supporting documentation by Council’s Environmental
Health Officers. Please note that the installation of high
water volume features, such as spas, will require
additional disposal field area to be installed.
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i
Note: a habitable room
includes any room that may
be closed off with a door,
such as a study, library or
sunroom that could be used
for the purposes of a
bedroom.
Page 14
Sizing of effluent disposal systems
Due to an increased average rainfall in the northern part of the Shire, an additional 10%
recommended minimum disposal area is required to cope with the additional wet conditions.
Generally any property north of the townships of Rokewood and Maude are classified as medium
rainfall areas. Detailed mapping on this criteria is available in Map 12 of Council’s ‘Domestic
Wastewater Management Plan – Volume 2’, which is available on our website.
Other important considerations:
 All disposal fields must be a permanent dedicated area within the property boundaries
 It must be protected from vehicles and livestock
 Do not place your disposal field in a paddock that will be planted and harvested
 For construction of new dwellings it is important to think about your landscaping plans at
septic tank application stage, as irrigation can also be used in garden beds.
Absorption/transpiration trenches (with PVC pipe/reln or arch drain)
Number of habitable
rooms
Minimum disposal area
required (Low rainfall)
Minimum disposal area (Medium rainfall)
1
60 m2
66 m2
2
90 m2
99 m2
3
120 m2
132 m2
4
150 m2
165 m2
5
180 m2
198 m2
Subsurface irrigation (secondary treated effluent only)
Number of habitable
rooms
Minimum disposal area
required (Low rainfall)
Minimum disposal area (Medium rainfall)
1
150 m2
165 m2
2
225 m2
248 m2
3
300 m2
330 m2
4
375 m2
413 m2
5
450 m2
495 m2
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Setbacks/buffer distances
Setbacks are predetermined distances that must be maintained between site features and any
part of the treatment system and disposal field.
These distances have been determined by the Environment Protection Authority and must be
adhered to at all times. The following setback distances are required for all septic tank system
disposal fields.
Don’t forget that setback distances also apply to features on neighbouring properties.
Setback distances (m)
Landscape feature or structure
Building
Wastewater field up-slope of building
Wastewater field down-slope of building
Wastewater up-slope of cutting/escarpment
Allotment boundary
Wastewater field up-slope of adjacent lot
Wastewater field down-slope of adjacent lot
Surface waters (up-slope of)
Dam, lake or reservoir (potable water supply, includes water
for food production)
Waterways (potable water supply)
Waterways, wetlands (continuous or ephemeral, nonpotable); estuaries, ocean beach at high-tide mark; dams,
lakes or reservoirs (stock and domestic, non-potable)
Groundwater bores
Potable or non-potable
Services
Water Supply pipe
Wastewater up slope of potable supply channel
Wastewater field down-slope of potable supply channel
Gas supply pipe
In-ground water tank
Stormwater drain
Recreational areas
Children’s grassed playground (school, council, community or
other children’s playground)
In-ground swimming pool
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Primary
treated
effluent
Secondary
sewage and
greywater
effluent
6
3
15
3
1.5
15
6
3
3
1.5
300
150
100
100
60
30
20
20
3
300
20
3
15
6
1.5
150
10
1.5
4
3
6
3
6
3
Page 16
Permit to Install
Council will issue a Permit to Install if the proposed system is suitable for the development, the
application is filled in correctly (including a detailed plan on the page provided) and copies of any
other information required are provided.
If a permit has been issued and the applicant changes details of the system and/or the registered
plumber, then an application to amend a permit must be completed. A fee will apply for this
application. This form can be found on our website.
The Permit to Install is valid for two (2) years from the date
of issue. Should the works take longer than the two (2)
years, the applicant must complete an Application for a
Permit Extension prior to the expiry date. A fee will apply for
this application. This form can be found on our website.
NO work can commence on the installation of your system
until you have received your septic tank permit. Please note:
All permits are issued with conditions. Compliance with the
permit conditions is required.
i
Note: please allow up to
four weeks for the
processing of your Septic
Tank Application.
Inspections of your system
All septic systems require mandatory inspections which must be conducted by Council’s
Environmental Health Department.
Inspection are carried out a) prior to issuing a Permit to
Install, b) when the system is being installed and c) a final
inspection when the system has been completed.
You or your installer must contact Council’s Environmental
Health Officer two (2) working days prior to installation to
arrange a suitable time for the installation inspection.
Allow ten (10) working days after final documentation is
received (refer to the next page) for a final inspection to be
carried out and a Certificate to Use being issued.
i
Note: all inspections are
mandatory and will
determine whether Council
will issue a
Certificate to Use. Failure to
book in an installation
inspection may result in
your Certificate to Use not
being issued.
To arrange your inspection please contact Council’s
Environmental Health Department on
03) 5220 7111.
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Certificate to Use
The following additional information is required prior to a final
inspection and a Certificate to Use being issued:




A copy of the Plumbing Industry Certificate
If a package treatment plant is installed, a
commissioning certificate
If a pump well is installed, an electrical certificate, and
An ‘as installed’ plan.
i
Note: the issuing of a
Certificate to Use is a legal
requirement. Your system
should not be used until
approval has been
granted. Fines apply when
a system is used without
approval.
Maintenance
Owners of a septic tank system must comply with the Certificate to Use and relevant EPA
certificate of approval and maintain their system in good working order.
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