Grease arrestors installation guidelines

What you need to know about installing grease arrestors.

Grease arrestors must be installed by licensed plumbers according to our trade waste requirements and the manufacturer’s instructions. Incorrect installations can affect the ability to service the grease arrestor to the required standard and allow greasy wastewater to discharge to the wastewater system where it can cause blockages and overflows to the environment.



Sizing of grease arrestors for the retail food industry


Grease arrestors are to be constructed in such a manner that the walls and floor are impenetrable, and the inner surface acid resistant.


Grease arrestors may be constructed, prefabricated or precast. The design, material used and size must be accepted by Water Corporation prior to installation.

Typical grease arrestor drawing


Where grease arrestors require baffles the minimum thickness is 19mm. Baffles constructed of uPVC or HDPE must be reinforced.


Gas tight covers to an arrestor are required where:
  • there is vehicular traffic
  • there is pedestrian traffic
  • the arrestor is subjected to stormwater intrusion
  • the arrestor is installed inside a building
  • light duty gas tight lids are recommended when grease arrestors are installed above ground.

Vertical clearance

Ensure there is vertical clearance above the grease arrestor, greater than the maximum depth of the grease arrestor and allows servicing of the arrestor in accordance with our standards.

Safe access

All above ground grease arrestor installations are required to have a platform and steps manufactured to Australian Standards 1657-1992 for safe access to inspect and maintain the grease arrestor.

Fixed suction lines

Fixed suction lines shall terminate with a camlock fitting and ball valve adjacent to the grease arrestor and also where the pumping contractor locates their vehicle. Fixed suction lines are not permitted inside grease arrestors.


Grease arrestors should be located exterior of the building wherever practicable.

Maintenance and cleaning

Maintaining and cleaning of grease arrestors

Hose tap

A hose tap should be installed within 6 metres of the arrestor and must have an appropriate testable backflow prevention device fitted as required by plumbing standards.

Inlet connection

The inlet connection cannot enter at the side of the grease arrestor.

Sampling point

Sample points can not be used as a relief disconnector gully.

Trade waste sampling point HX33-011-030-01

Dishwashing and glass washing machines

Dishwashing machines and glass washers can not discharge to grease arrestors.


  • All industrial waste grease arrestors are to be vented to atmosphere as, as per venting trade waste grease arrestors HX33-010-010-01.
  • Air admittance valves are not to be used on the grease arrestor vent or the sealed trade waste sampling point.
  • A vent from a grease arrestor situated in a multi-storey building may connect to the relief vent system above first floor level, provided the vent pipe is not reduced in the direction of its opening to the atmosphere and the total number of fixture units allowed for in the size of the relief vent are not exceeded.
  • Grease arrestors connected in series may combine the educt vents above ground level providing that where the vent interconnects, the vents will be increased 1 size in diameter.


All associated plumbing work is to comply with Water Services Licensing (Plumbers Licensing and Plumbing Standards) Regulations 2000 and AS/NZS 3500.1:2003 and AS/NZS 3500.2:2003.

Grease arrestor plumbing work case study

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