How Often Should a Grease Trap Be Cleaned?

There is no single correct interval, and any contractor who quotes one without seeing your unit is guessing. Frequency depends on the capacity of the interceptor, how much fats, oils and grease your kitchen actually produces, and how quickly the unit reaches the point where it stops separating grease effectively.

The one-quarter guideline

A widely used industry rule of thumb is that an interceptor should be serviced before accumulated grease and solids reach roughly a quarter of the unit's total capacity. Past that point, the effective volume left for separation drops and grease starts carrying through to the sewer. It is a practical trigger, not a regulation — the reason it works is that it is based on the unit's condition rather than the calendar.

What shortens the interval

• Small trap capacity relative to kitchen output
• Fryer-heavy, wok-heavy or high-volume menus
• Long operating hours or seven-day service
• Multiple kitchens sharing one interceptor
• Poor kitchen-side practices, such as scraping grease into sinks

What lengthens it

• Generously sized in-ground interceptor
• Low-FOG menu — cold prep, bakery, beverage-led
• Limited operating hours or seasonal trade
• Good kitchen practices: dry-wiping pans, scraping solids to waste, strainers in use

How to actually set your interval

Measure. On each visit, record the grease cap thickness, liquid level and solids depth before pumping. After two or three services you know the fill rate, and the interval stops being a debate. If a unit reaches the quarter mark in seven weeks, a quarterly schedule was never going to hold.

In our maintenance programs, this is exactly what the recorded measurements are for: the interval gets tuned to your system instead of applied from a template.