Grease Trap Cleaning vs. Hood Cleaning: Why They're Not the Same Service

“We just had our grease trap pumped last month — we’re covered, right?” We hear a version of this question more often than you’d expect, usually right after a kitchen fails a fire marshal inspection it thought it had already passed. Grease trap cleaning and hood/exhaust cleaning are two completely separate services, regulated by two different authorities, protecting against two different failure modes. Being current on one tells you nothing about the other.

What grease trap cleaning actually covers

Your grease trap (or grease interceptor) sits in your plumbing line, catching fats, oils, and grease before they reach the municipal sewer system. It’s regulated under your local water and sewer authority’s FOG (Fats, Oils, and Grease) program — in Charlotte, that’s Charlotte Water, not the fire marshal. Keeping it pumped and documented protects you from sewer backups, wastewater violations, and the fines that come with them. It has nothing to do with fire risk, and nothing to do with what’s happening above your cookline.

What hood and exhaust cleaning actually covers

Hood and exhaust cleaning addresses an entirely different grease problem: the grease that vaporizes during cooking and coats the inside of your hood, plenum, ductwork, and rooftop exhaust fan. That buildup is regulated under NFPA 96 — the national fire code standard — and enforced locally by your fire marshal’s office, not your water utility. It’s one of the leading causes of commercial kitchen fires, which is exactly why it gets inspected separately, on its own schedule, by its own authority.

Why the confusion actually costs restaurants

The two systems get mixed up constantly because they’re both about “grease” and both feel like compliance checkboxes. But a kitchen can have a spotless, recently-pumped grease trap and still be carrying months of hardened grease inside its ductwork — invisible from the kitchen floor, and exactly what a fire marshal is trained to look for. We’ve walked into inspections where the owner genuinely believed their grease trap receipt would cover them, only to find out the fire marshal was asking about a system they’d never had professionally cleaned. That’s not a paperwork mix-up you want to discover during an active inspection.

Do you need both, and how often

Almost every commercial kitchen needs both services — they’re not optional alternatives to each other. Grease trap pumping frequency is set by your local water authority based on your interceptor size and grease volume; check with Charlotte Water or your local utility for your required schedule. Hood and exhaust cleaning frequency is set by NFPA 96 based on your cooking volume and fuel type, ranging from monthly for solid-fuel operations to annually for low-volume kitchens — our frequency calculator can tell you where your kitchen falls in about 30 seconds, and our full breakdown of NFPA 96’s frequency tiers covers the reasoning behind them.

The bottom line

Keep both current, but don’t let one give you false confidence about the other. If you can’t remember the last time someone actually opened up your hood, ductwork, and rooftop fan — not just wiped down the visible hood surface — that’s worth checking before a fire marshal checks it for you. Request a free quote and we’ll tell you honestly where your system stands.