Grease trap FAQ

In plumbing codes both are grease interceptors. A "grease trap" usually means a small hydromechanical unit under or near the sink, rated by flow (gallons per minute, e.g. 20–50 gpm) and sized with the PDI G-101 sink method. A "grease interceptor" usually means a large gravity tank, often in-ground outside, rated in gallons (commonly 500 gallons and up) and sized by drainage fixture units (UPC) or peak flow × 30 minutes (IPC). Many cities require the gravity type for new restaurants; check your city page.

Many city FOG ordinances require pumping before floating grease plus settled solids reach 25% of the trap or interceptor's liquid depth or capacity. Many pair it with a maximum interval (often 90 days for gravity interceptors). See which cities use it on the comparison table.

In the city ordinances we track, the food service establishment (the owner or operator of the restaurant) is responsible for installing, maintaining and pumping its grease trap or interceptor, hiring an approved hauler where required, and keeping the pumping records on site. Check your lease for who pays, but the city holds the establishment responsible.

It depends on the city. Ordinances typically allow civil penalties per violation, often counted per day, plus charges for sewer blockages or overflows the restaurant causes. Cities with penalty amounts in their source are shown on each city page under "Fines & penalties".

Whatever your local sewer authority requires: commonly before 25% full and at least every 90 days for gravity interceptors, and more often (often weekly or monthly) for small under-sink traps. See the guide and your city page.