How Often Should a Grease Trap Be Cleaned?

Short answer: for most commercial kitchens, every one to three months, or whenever the trap reaches 25% of its capacity, whichever comes first. Your trade waste agreement sets the legal minimum, so you do not get to pick a timetable that suits you. Here is how it actually works in Australia.

The general rule: every 1 to 3 months

For busy cafes, takeaways and hotels, the standard interval is every one to three months. Lighter-use sites can stretch a little longer. High-volume fryers often need a pump-out monthly. The right number depends on how much fat, oil and grease your kitchen puts out.

The 25% rule decides it for you

The cleaner test is the 25% rule. Pump out when combined grease and solids reach 25% of the trap's capacity. Past that point, the trap stops separating properly and grease starts slipping into the sewer. If your trap hits 25% in six weeks, six weeks is your cycle, regardless of what the calendar says.

Who actually sets your frequency

You do not choose this on your own.

Your water authority and council

Your local water authority and council set and enforce the interval, through bodies like Sydney Water, Queensland Urban Utilities or SA Water. The rules vary by area.

Your trade waste agreement

When you set up a food business, you get a trade waste permit that spells out how often your trap must be serviced. That document is the one that matters. Follow it, keep your records, and you stay compliant.

What changes how often you need it

Menu and volume drive everything. Deep-frying, lots of dairy, heavy meat prep and high covers all load the trap faster. A quiet cafe and a flat-out burger joint with the same size trap will run very different cycles.

The cost of getting it wrong

Skip services and the trap overflows, the drains back up, and you face fines or a forced closure. Over-clean and you waste money. The 25% rule and your trade waste agreement together give you the right number, so you pay for what you need and nothing more.

The bottom line

Clean every one to three months, or at 25% capacity, whichever comes first, and never less often than your trade waste agreement says. Match the cycle to your kitchen's output and you stay compliant without overspending.

Not sure what your cycle should be? Compare quotes from licensed operators near you. Related reads: the 25% rule explained, cleaning costs, and Australian regulations.