How Often Should a Restaurant Pump Its Grease Trap? A Boston-Area Guide

Every restaurant owner in Greater Boston eventually asks the same question: how often do I really need to pump the grease trap? Most of the bad answers come from people trying to sell you more service, or to talk you out of any service at all. The honest answer has two parts: what your local authority requires, and how fast your particular kitchen actually fills its trap.

Who sets the rules

Grease trap requirements — how full a trap may get, how often it must be serviced, and what records you keep — are set and enforced locally by your sewer authority and board of health. They are not identical everywhere, so confirm yours before you set a schedule. Boston operators can start with the Boston Water and Sewer Commission's commercial kitchen grease trap guidelines.

Whatever the local limit is, the physics are the same: as the grease and solids layers grow, a trap separates less effectively and starts passing grease into the line downstream.

Planning ranges by kitchen volume (not a legal standard)

• High-volume fry / pizza / burger kitchens: monthly pumping. Often every 3 weeks for the busiest spots.
• Mid-volume sit-down restaurants, hotels, cafeterias: every 6–8 weeks.
• Low-volume cafés, bars, dessert shops: every 90 days.
• In-ground interceptors (500–2,000 gal): typically quarterly — but flow varies, so we measure first.
• Food trucks & ghost kitchens: usually monthly, depending on hours.

Pumping is not service

The most common mistake we see is a kitchen that schedules a "pump-out" with a national hauler — the truck shows up, runs the vacuum hose for ten minutes, and leaves. The trap is empty. The walls are still coated. The baffles are loose. The tees are broken. Grease can bypass the trap before the next visit.

A real grease trap service is six steps every visit:

1. Pump out all FOG, solids, and gray water.
2. Scrape the walls, lid, and baffles down to bare metal.
3. Pressure-rinse the trap interior.
4. Inspect inlet and outlet tees (damaged tees let grease bypass the trap).
5. Jet the grease line downstream when warranted.
6. Hand you a written service record and waste manifest.

The grease line downstream matters too

If the line between your trap and the city sewer is coated in old grease, even a perfect trap won't keep your kitchen drains flowing. Hydro jetting the grease line every 3–6 months for high-volume kitchens (and yearly for everyone else) restores the pipe to true diameter and resets the clock. We camera, jet, and document.

What this costs in Greater Boston

• Under-sink trap (20–50 gal) pump & clean: $175–$375
• Mid-size interceptor (75–250 gal): $275–$525
• In-ground interceptor (500–2,000 gal): $325–$750+
• Grease line hydro jet (downstream of trap): $300–$600
• After-hours / weekend surcharge: +$95–$185

Compare those numbers to a single failed health inspection, a weekend shutdown for a backed-up kitchen drain, or an emergency pump-out on a Friday night. The math is never close. Get on a schedule and stay on it.