INSTALLING AND OPERATING A GREASE INTERCEPTOR TRAP
Trade Waste Approval requirements
Operation of a Grease Trap
Trade Waste Approval is required for any food
To ensure operational efficacy, each grease trap must
business prior to discharging trade waste to sewer.
be adequately maintained and serviced regularly.
For most businesses, it will be a requirement of your
Townsville Water and Waste will determine the
Approval that appropriate pre-treatment is installed and
required frequency of servicing and this will be a
maintained.
condition of the Trade Waste Approval.
All food business are required to install dry basket
Commercial
arrestors (Scrap Catches) in food preparation sinks
dischargers who regularly maintain and service their
and any floor drains.
grease trap will be considered to have complied with
Food
(Category
1)
trade
waste
the sewer admission limits.
In addition, for greasy food waste, a grease trap is
required. Sizing will depend on the type of business,
Failure to operate and maintain the grease trap to the
but will be no less than 1000L.
required standards may result in a breach of the sewer
See the attached
fixture ratings for an estimate of grease trap size.
admission limits or other conditions of a Trade Waste
Approval.
Townsville Water and Waste will take
Townsville Water and Waste reserves the right to
appropriate compliance action, which may include
refuse trade waste approval to discharge to sewer
cancellation of Trade Waste Approval.
unless pre-treatment requirements are satisfied.
Grease Trap Servicing
Exceptions
Servicing is necessary to clean the trap of coagulated
Alternative pre-treatment devices may be considered
grease, food solids and any other particles which could
in the following circumstances:
block or obstruct the outlet pipe. At each service, it is
» the installation of a typical grease trap is not viable
required that:
due to site constraints.

the grease trap is pumped out completely;
More regular servicing of an under-sized grease trap

the internal surfaces are scraped and/or hosed off;
The approval of an alternative pre-treatment system

any maintenance requirements, such as broken
» if the trade waste generator can provide documented
evidence of the pre-treatment systems performance.
may be subject to additional conditions attached to the
baffles are noted;
Trade Waste Approval.

the trap is at least third-filled with water when
complete. This is best done by the business
Installation of approved pre-treatment devices
operator in the first shift after servicing, i.e. leave
All pre-treatment equipment must be installed as per
the tap running for 30-60 minutes.
manufacturers specifications and in compliance with all
relevant
legislation,
standards
and
Council

Townsville Water and Waste is advised within a
requirements (e.g. AS 3500, Plumbing & Drainage Act,
month that the service has been completed and of
Water Supply [Safety and Reliability] Act 2008, etc).
any maintenance issues noted. It is preferred that
this advice be provided by service contractors in a
An extract of Standard Plumbing and Drainage
Regulation 2003 is attached.
monthly spreadsheet.
The following fixture rating can be used to assess the
GREASE TRAP SIZING
Townsville
Water
and
grease interceptor trap size, provided the minimum
all
size is exceeded. The recommended grease trap size
commercial food business have a properly sized
Waste
require
that
is the sum of the fixture ratings for all installed fixtures.
grease interceptor trap to ensure greasy wastes are
E.g. for a kitchen with 2 commercial sinks, and a
not discharged to sewer.
medium sized dishwasher the grease trap size is 1400
litres (300 + 300 + 800).
As a minimum, any new food development or
renovation requires a 1000L grease interceptor trap.
Townsville Water and Waste accepts NO responsibility
for the incorrect sizing or installation of a grease
interceptor trap.
For a shared grease interceptor trap the minimum size
will be 1000L plus 1000L for each additional food
Townsville Water and Waste encourages trade waste
business connected to the grease trap. Depending on
generators to secure the services of a licensed
the number of fixtures in the kitchen/s the size of the
plumber and/or hydraulic consultant to assist with the
grease trap may be required to be bigger than the
design and installation of the grease interceptor trap.
minimum (in accordance with Standard Plumbing and
Drainage Regulations 2003, see attached).
Grease Interceptor Trap Fixture Ratings
Fixtures/Fittings
Capacity (Litres)
Kitchen Sink
100
Commercial Sink (Double Bowl or Pot)
300
Rinse Sink
200
Basin
30
Floor Waste
10
Tundish
10
Glass Washers
250
Dishwasher
Potato peeler
Small (under bench)
400
Medium
800
Large
1200
Small
100
Medium
200
Large
400
Wok Burner (per burner)
100
Steamer
100
Water Heated Baine Marie
50
Garbage Disposal Unit
500
(Note 1)
NOTES
1.
The use of garbage disposal units is not allowed in commercial kitchens, hospitals or nursing homes unless specific
permission has been obtained from Townsville Water and Waste.
2.
In the case of a shared grease interceptor trap, the minimum size of the grease interceptor trap should be calculated
based on the capacity of the total fixtures for all businesses to be connected to the grease interceptor trap.
GREASE TRAP INSTALLATION – EXTRACT FROM STANDARD PLUMBING AND
DRAINAGE REGULATION 2003
Division 3 Arrestors
39 Requirements for grease arrestors
(1) A grease arrestor on premises must—
(a) be installed in an accessible position,
preferably outside a building, and as close
as practicable to the appliance or fixture
the arrestor serves; and
(b) have a childproof cover or, if it is in an
area subject to motor vehicle traffic, a
suitable heavy duty cover; and
(c) if the arrestor is installed inside a building
and in an area used for food preparation—
(i) have a cover that is airtight; and
(ii) have its arrestor chamber fitted with a
vent of a size of at least 50mm; and
(d) have a capacity below the invert of the
outlet of at least twice the total capacity of
the appliances and fixtures connected to it
or, if the local government requires a larger
capacity for the arrestor, the larger
capacity; and
(e) have inlet and outlet ventilation of the
standard for sanitary plumbing.
(2) The following must be fitted with a trap—
(a) an appliance or fixture discharging to the
arrestor;
(b) the arrestor outlet.
(3) The size of the arrestor outlet must be at least
100mm.
(4) The clean-out point for the arrestor must be
accessible.
(5) The distance from the top of the arrestor to the
outlet invert must be at least half the depth of the
arrestor below the outlet invert.
(6) The outlet invert level of the arrestor must be
at least 50mm below the inlet invert level.
(7) Any outlet pipe from the arrestor must—
(a) be of a diameter approved by the local
government; and
(b) have a cross-sectional area of at least the
combined cross-sectional areas of the
incoming waste pipe.
(8) The design and location of the ventilation for
the arrestor must be as approved by the local
government.
(9) In approving the design and location of the
arrestor’s ventilation under subsection (8), the
local government must have regard to the
arrestor’s design and the location of trap water
seals in the arrestor.
40 Connection of appliances and fixtures
to grease arrestors
(1) If an appliance or fixture is connected to a
grease arrestor in a way that complies with this
section, the appliance or fixture is not required to
be separately vented in the way required under the
applied provisions.
(2) The connecting pipe must be as short and
direct as possible but, if its size is 50mm or less, it
must not be longer than 2.5m.
(3) If the appliance or fixture is for collecting
greasy discharges from floor areas, it must be
connected to the inlet pipe of the arrestor in 1 of
the following ways—
(a) separately and uninterrupted by a trap
water seal or air gap;
(b) in combination through a 100mm or larger
pipe with an upstream vent.