Grease Trap vs. Grease Interceptor: What’s the Difference and Which Does Your Business Need?
June 3, 2025
If you operate a commercial kitchen in the Bay Area, you’ve likely heard the terms grease trap and grease interceptor—but what exactly is the difference, and why does it matter? While both devices serve the same essential purpose—keeping fats, oils, and grease (FOG) out of the sewer system—they’re designed for different volumes, flow rates, and facility types.
What is a Grease Trap?
Our lead grease trap service technician David pumps out a small 20-gallon grease trap located inside a hotel that serves only continental breakfast.
A grease trap is a small, point-of-use unit typically located inside the kitchen under a sink or floor drain. It captures FOG from a single fixture or small set of fixtures before it can enter the plumbing system.
Common locations with grease traps:
- Coffee shops
- Bakeries
- Small cafes
- Quick-service restaurants (QSRs)
- Older restaurants with space constraints
Maintenance needs:
Because of their smaller size (usually 10–100 gallons), grease traps fill quickly and often need to be cleaned weekly or bi-weekly, depending on the volume of use. Neglecting routine maintenance can lead to backups, odors, and non-compliance with local wastewater regulations.
What is a Grease Interceptor?
A grease interceptor located at a busy winery tasting room kitchen in Windsor, California.
A grease interceptor is a much larger unit—often 500 to 2,000+ gallons—located outside the building, underground. It’s designed to handle high flow rates from multiple kitchen fixtures and is common in larger operations.
Common locations with grease interceptors:
- Full-service restaurants
- Hotels
- Hospitals
- Schools and universities
- Shopping malls and food courts
- Large-scale commissary or production kitchens
Maintenance needs:
Because of their size, interceptors are usually cleaned monthly or quarterly, though frequency depends on usage and local regulations. Some facilities may be required by their jurisdiction to clean more often to stay under the allowable FOG and solids limit (e.g., 25% in San Francisco).
📊 Want to know what your local requirements are? Check out our guide to FOG Limits by Jurisdiction.
Can a Facility Have Both?
While it’s rare, some locations do have both a grease trap and an interceptor—usually in complex setups with multiple kitchens or when certain fixtures are not connected to the main interceptor. In these cases, both units must be serviced separately on their own schedules.
Key Differences at a Glance:
| Feature | Grease Trap | Grease Interceptor |
|---|---|---|
| Size | Small (10–100 gallons) | Large (500–2,000+ gallons) |
| Location | Indoors (under sink/floor) | Outdoors (usually underground) |
| Typical Facilities | Small cafes, bakeries, QSRs | Full-service restaurants, hotels |
| Flow Rate | Low | High |
| Maintenance Frequency | Weekly to bi-weekly | Monthly to quarterly |
💡 Wondering what service costs look like? Check out our full breakdown here: How Much Does a Grease Trap Cleaning Cost in the Bay Area?
Why It Matters
Understanding the type of system your kitchen has—and how often it needs service—is key to staying in compliance with local wastewater ordinances and avoiding costly plumbing issues. Whether you have a trap or an interceptor, regular service paired with proper documentation is essential.
At North Bay Restaurant Services, we clean and maintain both traps and interceptors. Our techs use before-and-after photos, measure FOG content, and provide digital follow-up reports through our service app so you always know your system is in compliance.
Not Sure What You Have?
We’re happy to inspect your setup and advise on the best maintenance schedule to stay compliant with local regulations.
📞 Contact us today to schedule a free consultation and stay ahead of the mess.
Written by Brittney Bailey
Director, North Bay Restaurant Services
Since 2016, Brittney has led the administrative and customer service operations at North Bay Restaurant Services, supporting thousands of commercial kitchens across the Bay Area. She specializes in coordinating service for high-volume restaurants, hotels, and fine dining establishments—where timing, cleanliness, and compliance are non-negotiable. Brittney prides herself on delivering concierge-level customer service in an industry not known for it, bringing Michelin-level attention and professionalism to every account.
