Grease Trap Cleaning Frequency by Restaurant Type (2026 Benchmarks)
"How often should we pump the trap?" has one legal answer — before FOG hits 25% of capacity — but what that means in practice depends almost entirely on what you cook. Here are working benchmarks by kitchen type, based on typical FOG output, that you can use as a starting interval and then tune with actual measurements.
Benchmarks by Kitchen Type
| Kitchen type | FOG output | Typical cleaning interval | Notes |
|---|---|---|---|
| Fast food / QSR with fryers | Very high | Every 30 days | Fryer-heavy menus saturate small traps fastest; many QSRs need monthly service even with a large interceptor. |
| Full-service restaurant | High | Every 30–60 days | Scratch kitchens with grills and sauté lines; tune by FOG depth measurements. |
| Ghost kitchen / delivery-only | High | Every 30–60 days | Delivery menus skew fried; output per square foot often exceeds dine-in. Shared facilities should meter by tenant volume. |
| Pizzeria | Moderate | Every 60 days | Cheese and oils add up slower than fryer waste, but dough and toppings contribute solids. |
| Bakery | Moderate | Every 60–90 days | Butter and shortening are FOG; donut/fried programs move a bakery into the 30–60 day class. |
| School / institutional cafeteria | Moderate–high | Every 30–60 days | High meal counts; many districts standardize on monthly during the school year. |
| Hotel kitchen / banquet | High, spiky | Every 30–60 days | Banquet weekends can load a trap as much as a normal month — schedule extra service around event season. |
| Café / coffee shop (light prep) | Low | Every 90 days | Milk fat counts as FOG; espresso-and-pastry shops are usually fine at the legal maximum interval. |
| Bar with fryer menu | Moderate | Every 60 days | Wings-and-fries menus produce more FOG than owners expect. |
| Brewery taproom with kitchen | Moderate | Every 60–90 days | Trub and spent-grain handling are separate problems — keep them out of drains entirely. |
| Food truck (at commissary) | Varies | Per commissary schedule | The commissary's trap and compliance duty cover discharges; confirm your dumping is logged. See grease traps for food trucks. |
Four Factors That Move Your Interval
- Menu. Fryers are the dominant variable. A single high-volume fryer program can halve your interval.
- Trap size vs. seat count. An undersized trap (very common in older buildings) fills to 25% quickly no matter the menu. If you're cleaning monthly and still hitting 25%, the trap may simply be too small — see the size guide.
- Covers per day. Meals served scales FOG nearly linearly. A seasonal rush (summer patio, holiday banquets) deserves an extra service.
- Local law. Many cities cap the interval (90 days is common) regardless of measurements, and some set stricter rules by business type. Check your state in the compliance guide.
How to Tune From the Benchmark
- Start at the benchmark interval for your kitchen type above.
- Measure FOG depth monthly for one quarter (method in our inspection checklist).
- If you hit 25% before the scheduled service — shorten the interval. Consistently under 15% at service time — you may lengthen it, up to your local legal maximum.
- Document everything in the maintenance log; measurements are your defense for a longer interval.
Frequently Asked Questions
What is the 25% rule for grease traps?
Clean the trap before fats, oils, and grease (floating cap plus settled solids) occupy 25% of its liquid capacity. Past that point, separation efficiency collapses and grease passes through to the sewer — which is what triggers violations. Most municipal codes either cite the 25% rule directly or set a maximum interval like 90 days, whichever comes first.
Do ghost kitchens and food trucks have to follow the same rules?
Yes — any commercial food preparation that discharges to a sanitary sewer falls under FOG programs. Ghost kitchens often have higher FOG output per square foot than dine-in restaurants (delivery menus skew fried). Food trucks typically discharge at their commissary, which carries the compliance duty.
My trap never seems full. Can I stretch the interval?
Maybe — but measure, don't guess. Check FOG depth monthly for a quarter; if you're consistently under 25% at your current interval, your jurisdiction's maximum interval (often 90 days) becomes the binding constraint, not the 25% rule. Document the measurements so you can defend the longer interval to an inspector.
Does cleaning frequency change my price?
Per-visit price falls slightly with contracted recurring service (15–30% below one-off rates), and dramatically versus emergencies (50–100% premium). Annual cost is usually lowest at the correct interval: too-rare cleaning risks backups and fines that wipe out years of savings. See the pricing guide.
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