What Happens If You Never Pump a Grease Trap

The decay curve

Weeks 1–4: silent accumulation. The trap does its job. The grease cap thickens, solids settle. Nothing visible. This is when pumping is cheapest.

Weeks 4–8: the smell phase. Anaerobic decomposition starts — the sour dish-pit odor. Separation efficiency is falling; grease is beginning to slip downstream and coat your lateral line. Pump now and you’re still at standard pricing.

Weeks 8–12: the slow-drain phase. The trap crosses the parish’s one-third ceiling — you’re now out of compliance (Sec. 2:273) whether or not anything has visibly failed. Drains throttle. Hardened grease from weeks 4–8 is waiting in the line.

Day ~90+: the forced exit. One of three things happens, and you don’t choose which: an overflow during service; an inspector visit that becomes a citation with deadlines; or a shared-line backup where the parish bills every business on the line — and the one without maintenance records (Sec. 2:272(6)) has no defense. A neglected trap also compacts: the eventual cleaning takes hose time and hardened-solids work that gets billed like the archaeology it is.

The arithmetic nobody runs

A year of on-schedule service for a typical indoor trap lands in four figures. One bad week — emergency pump-out at holiday rates, a line jetting, a re-inspection, lost Friday covers — can match it. The trap gets pumped either way; the only choice is whether it happens on your calendar or the trap’s.