When is a grease trap required in a commercial kitchen?
Summary (TL;DR)
A grease trap (grease arrestor) is mandatory for any commercial food preparation business (cafes, restaurants, bakeries) that discharges fats, oils, and grease (FOG) into the sewer. The exact sizing and installation requirements are dictated by the local water utility (e.g., Urban Utilities, Gold Coast Water), not just AS/NZS 3500.2.
Trade Waste and Grease Traps
Fats, oils, and grease are the enemy of the sewer network. They solidify in the pipes, causing massive "fatbergs" and blockages. To prevent this, water utilities require commercial kitchens to install a grease trap to intercept the FOG before it reaches the sewer.
Who Needs One?
Almost any business that cooks or prepares food commercially requires a grease trap. This includes:
- Restaurants and cafes
- Takeaway shops and bakeries
- Butchers and delicatessens
- Commercial caterers
Sizing the Grease Trap
While AS/NZS 3500.2 provides general installation guidelines, the size of the grease trap is determined by the local water utility's Trade Waste policy. Sizing is usually calculated based on:
- The number of seats in the restaurant
- The type of equipment (e.g., woks, deep fryers)
- The peak flow rate of the fixtures discharging into it
Minimum sizes typically start at 1000 litres for a small cafe, up to several thousand litres for a large restaurant.
What Connects to It?
All fixtures that handle food waste or grease must drain to the grease trap, including kitchen sinks, dishwashers, and floor waste gullies in the food prep area. Hand wash basins and toilets must not connect to the grease trap.
Navigate Trade Waste Approvals Easily
Trade waste approvals can be complex. Use TradeDesk.now to store utility contact details, track your trade waste applications, and access the specific grease trap sizing guidelines for your local council area.