Grease Trap Cleaning: Schedule, Rules, and Costs

Published 07.28.2026. Written for restaurant operators and facility managers. This is a plain-language summary; your local sewer authority sets the binding rules.

Grease trap pumping is one of the two recurring services every commercial kitchen is required to buy (hood cleaning is the other), because municipal sewer authorities regulate fats, oils, and grease, known as FOG, to prevent sewer blockages. Miss the schedule and the consequences arrive in order: odors, slow drains, a backup during service, then a citation.

The 25 percent rule

The standard most cities enforce: pump the trap before the combined layer of floating grease and settled solids reaches one quarter of the trap's liquid depth. Past that point the trap stops separating effectively and grease passes into the sewer, which is exactly what the ordinance exists to prevent. In practice, small under-sink traps at a busy kitchen hit 25 percent in 1 to 3 months, and large outdoor in-ground interceptors commonly run on quarterly schedules. Many jurisdictions also impose a maximum interval, frequently 90 days, even if the trap is not yet at 25 percent.

Full pump-out versus skimming

A proper service removes all contents, scrapes the walls and baffles, and hauls everything away, then the trap refills with water. Watch out for skimming services that remove only the floating grease layer and leave the settled solids: it is cheaper per visit and leaves the trap partly full, which shortens the interval and can violate local rules that require full evacuation.

What it costs

Pricing scales with trap size and access. Small indoor traps commonly cost in the low hundreds per service. Large outdoor interceptors, measured in hundreds or thousands of gallons, typically run several hundred dollars per pump-out, more where disposal fees are high or access requires long hose runs. Most haulers discount for a standing schedule, which is worth taking since the schedule is mandatory anyway.

The paperwork inspectors ask for

Use a licensed grease hauler and keep every manifest: the document showing the date, volume removed, hauler, and disposal site. Sewer authority inspectors ask for manifests going back a year or more, and missing records are treated like missed service. Kitchen habits extend the interval too: dry scrape plates into the trash, never pour fryer oil into drains (used fryer oil goes in a separate rendering barrel, and renderers often pay for it), and keep strainers in the sinks.

Find a service company

Companies handling restaurant plumbing and grease trap service are listed in the directory, alongside hood and exhaust cleaning companies for the other mandated service. See our NFPA 96 hood cleaning guide for that schedule.