Trade Waste

Trade waste is any liquid that is discharged into our sewerage system as the result of any trade or industrial process.

Careful disposal of trade waste is important to protect the environment and the health of our community.

Trade waste disposal is controlled by a bylaw to ensure safe disposal and to protect the sewerage system and treatment plants, which are essential city assets.

Grease traps

A grease trap pre-treats food waste before it enters the treatment system (either our sewer line or a private septic tank).

Commercial food premises and food preparation industries must have appropriate grease traps installed. With large businesses, more than one grease trap may be required.


Regardless of the size or design, all traps must be maintained on a regular basis appropriate to the level of use to ensure that they are working properly. 

You can improve the efficiency of a trap by minimising the amount of solids entering it. 

A cleaning frequency of 1 to 3 months is often acceptable. The trap size (volume) and the load placed on the trap all vary from business to business, resulting in different cleaning intervals for each trap.

We no longer permits servicing of these to be done by the business itself. This maintenance must be carried out by a contractor certified under the WasteMINZ Liquid & Hazardous Wastes Code of Practice.

You can find out about trap design, maintenance and information about the right trap for your business in our brochure for the food preparation and processing industry.

Trade Waste Information for the Food Preparation / Processing Industry(PDF, 475KB)

Waste grease

Waste grease must be stored in sealed containers on site before disposal.

Any minor spillages during the transfer of waste grease to these containers must be cleaned up immediately to prevent it from becoming a health risk and environmental pollutant.

Disposal of this waste should also be made through a contractor certified under the WasteMINZ Liquid & Hazardous Waste Code of Practice.

Waste containers should not be stored beside waterways or stormwater grates.

Lids should be tightly closed at all times.