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Commonly asked questions > Grease Traps > How do I work out which size Grease Trap I need?

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Grease Interceptor Sizing:

The sizing criteria outlined below is a Guide Only. WaterStore Poly Tanks will specify the sizing requirements at the time of application.


Sizing Grease Interceptors for Commercial Customers differs from Industrial Customers. Below is a guide to sizing grease interceptors for a commercial customer. Follow Steps 1 to 3 to determine the grease interceptor size.


Step 1:

Determine the grease interceptor size based on the seating capacity. 

Seating Capacity

Standard Grease Interceptor Sizes


600 Litre Grease Interceptor


1,100 Litre Grease Interceptor


2,000 Litre Grease Interceptor


3,000 Litre Grease Interceptor


4,000 Litre Grease Interceptor


5,000 Litre Grease Interceptor


Step 2:

Determine the grease interceptor size based on the fixtures in the food preparation/ kitchen areas.

Fixtures in the food preparation/kitchen areas

Allowance for fixture

Standard single bowl sink

100 litres per bowl

Pot Sink (single deep bowl)

150 litres per bowl

Floor Wastes (Food preparation area)

200 litres per bowl

Work table- number of burners

100 litres / burner

Garbage/bin wash (20m2 unroofed)

200 litres


200 litres

Steam “combi” oven

600 litres

Cleaners sink

50 litres

Hand basin (hands free) kitchen only

50 litres


Step 3:

The larger of the two grease interceptor sizes determined from step 1 and 2 should be considered as the estimated size. If the size of the grease interceptor determined in step 2 is larger than step 1 then the next standard size in grease interceptor (refer to table in step 1) should be used e.g. if the total ‘fixtures’ equals 850L then an 1,000 litre grease interceptor would be required.


Note: The minimum size grease interceptor for chicken shop whether it be BBQ, charcoal or fresh chicken shall be 1,000 litres.


Industrial Customers:

The size of the grease interceptor is determined by the maximum hourly flow rate. If the flow rate falls between the standard size grease interceptor, indicated below, then the next standard size grease interceptor shall be used, e.g. if the maximum hourly flow rate expected through the grease interceptor equals 900/L hour then an 1,000 litre grease interceptor would be required.

Grease Interceptor Sizes

600 Litre Grease Interceptor 

1,100 Litre Grease Interceptor

2,000 Litre Grease Interceptor

3,000 Litre Grease Interceptor

4,000 Litre Grease Interceptor

5,000 Litre Grease Interceptor


See FAQ "Installation Requirements" for more information