Opening a restaurant involves a long list of permits and inspections. The grease trap inspection is one that catches many new operators off guard, it is often administered by the local wastewater utility, not the health department, and it can delay your Certificate of Occupancy if you are not prepared. This guide walks through what the inspection involves, who conducts it, common reasons inspections fail, and exactly what to do before the inspector arrives. Need to find a licensed grease trap installation contractor before your inspection? Search at greasetraplocator.com.
Who Conducts the Grease Trap Inspection?
For a new restaurant, grease trap compliance may involve inspections from two different agencies:
1. Local building or plumbing department: The plumbing permit inspection confirms that the grease interceptor was installed per the approved drawings and the applicable plumbing code. This inspection is typically conducted by a licensed building inspector or plumbing inspector employed by the city or county.
2. Local wastewater utility or pretreatment program: The FOG compliance inspection confirms that the interceptor is properly sized for the operation, accessible for service, and meets the local FOG program's technical requirements. This inspection is conducted by an industrial waste analyst or FOG inspector from the sewer utility.
In many jurisdictions, both inspections must pass before the city issues a Certificate of Occupancy for a food service establishment. In some cities, the FOG inspection is a separate process that happens after opening but is still required before you can receive your food service permit renewal.
Check with your city's building department and wastewater utility early in the permitting process to understand which inspections are required and in what order.
Why the FOG Inspection Is Separate From the Health Inspection
New restaurant operators often expect the health department to handle all pre-opening inspections. Grease trap compliance falls under a different regulatory framework:
- Health inspections focus on food safety, temperature control, sanitation, and employee hygiene practices
- FOG inspections focus on wastewater pretreatment, ensuring that grease from your kitchen does not damage the municipal sewer system
These are separate programs, often in different departments with different inspectors. Passing a health inspection does not mean you have passed a FOG inspection, and vice versa.
Step 1: Confirm the Installation Is Complete and Correct
Before scheduling any inspection, verify that the installation is complete and matches the approved plumbing drawings. Walk through this checklist:
- The interceptor is the model and size specified in the permit application
- All plumbing connections to the interceptor are complete, no temporary fittings, no open connections
- Inlet and outlet tees are properly installed and facing the correct direction (inlet tee directs flow down into the trap; outlet tee picks up from below the grease layer)
- The flow control fitting (required for HGIs) is installed upstream of the interceptor inlet
- Access ports or hatches are accessible, not blocked by equipment, shelving, or construction debris
- The unit is level (gravity interceptors especially)
- Cleanout plugs are in place but accessible
- There are no visible leaks at any connection
If your plumber installed the unit, walk through this checklist with them before the inspection rather than relying on their assurance that it is done.
Step 2: Understand What the Plumbing Inspector Will Check
The plumbing inspector's primary concern is code compliance. They will:
- Verify that the installation matches the permit drawings
- Check that the unit bears the required certification mark (ASME A112.14.3 for HGIs; PDI G-101 for GGIs)
- Test the drain connections for leaks (typically by running water through the connected fixtures)
- Verify that all required cleanout access points are present
- Check that the unit was not installed in a prohibited location (some codes prohibit installation inside food preparation areas for gravity interceptors above a certain size)
Common plumbing inspection failures:
- Unit does not match the approved specifications in the permit
- Flow control fitting missing or wrong size
- Inlet/outlet tees missing
- Access ports blocked by built-in equipment
- Unit installed in a prohibited location
Step 3: Understand What the FOG Inspector Will Check
The FOG inspector's concerns are different from the plumbing inspector's. They are evaluating whether your installation will actually work as intended and whether you are set up for ongoing compliance. They will typically:
Verify sizing. The inspector may recalculate the required interceptor size based on the actual equipment list in your kitchen. If you added fixtures after the original permit was issued, a second prep sink, a floor drain near the grill, the inspector may flag that the unit is now undersized.
Check access. A grease trap that cannot be easily accessed by a service vehicle or by a technician with hand tools is a compliance problem. Outdoor interceptors need to be at grade level with manholes that a pumper truck can reach. Indoor interceptors need sufficient clearance for a technician to open them and use a pump hose.
Test flow. The inspector may run water through all connected fixtures to verify that flow reaches the interceptor and exits through the outlet rather than bypassing the unit.
Review your BMP plan. Many municipalities require new FSEs to submit a Best Management Practices plan as part of FOG registration. This is a short document describing your kitchen's FOG practices, dry wiping procedures, grease disposal methods, employee training. If your local program requires it, have it ready.
Verify registration. In some cities, you must register with the FOG program before the inspection occurs. If you have not completed registration, the inspector may defer the inspection until registration is on file.
Step 4: Schedule Service Before the Inspection
For a brand-new installation, the trap is empty. Most FOG inspectors want to see the unit full of water, this confirms there are no leaks and that the hydraulic seals are working correctly. Some inspectors also conduct a flow test that requires water to be actively running through the system.
Coordinate with your plumber to fill the unit with water before the inspection date. For an outdoor gravity interceptor, this may require running hoses into the tank. For an indoor HGI, running water through the connected sinks is typically sufficient.
Common Reasons New Restaurant FOG Inspections Fail
Based on common patterns reported by grease trap service professionals and inspection agencies:
1. Wrong size installed. The permit was based on an early equipment list; the final kitchen has more fixtures than originally planned. Solution: review your equipment list against your permit before the plumber finishes. If you added fixtures, tell the plumber before they close the walls.
2. Access blocked. The grease trap was installed in a location that made sense during framing but is now blocked by a walk-in cooler, a fixed equipment stand, or millwork. Solution: mark the interceptor location on your floor plan and give it to every contractor working in the kitchen.
3. Missing flow control fitting. For hydromechanical interceptors, a flow control fitting (also called a rate controller) is required upstream of the inlet. It is a small device that is easy to forget. Without it, flow rate through the trap exceeds the unit's design capacity during peak use.
4. Inlet/outlet tees backwards or absent. Some uncertified installers omit the internal tees or install them reversed. This allows grease to pass directly through the trap without being captured. An inspector will catch this immediately.
5. FOG registration not complete. In cities where FOG program registration is a pre-condition for the inspection, showing up for the inspection before registering wastes everyone's time.
6. Floor drains not connected. Floor drains near cooking equipment must be routed through the interceptor in most jurisdictions. Floor drains in other areas of the kitchen (near the handwashing station, in a dry storage room) typically do not. Verify with your local FOG program which drains must connect.
Step 5: What to Have Ready for the Inspector
On inspection day, have the following available:
- Copy of the plumbing permit
- Equipment certification sheet for the interceptor (make, model, PDI or ASME certification number)
- Kitchen layout showing all fixtures connected to the interceptor
- Your completed FOG program registration (if required by the local utility)
- Your BMP plan (if required)
- Your service contract or the name of a licensed hauler you will use for ongoing service
Having these documents ready demonstrates to the inspector that you are running a professional operation, not scrambling for compliance at the last minute.
After the Inspection: Setting Up Your Ongoing FOG Program
Once the inspection passes, the compliance work is just beginning. Set up these systems before your first day of service:
Service contract: Contact a licensed grease trap hauler and set up a service schedule. For a new restaurant, quarterly service is a reasonable starting point. You may need to adjust after your first few service visits reveal the actual rate of grease accumulation.
Record-keeping system: Create a physical or digital folder for your FOG manifests. Inspectors will ask for the last 12 to 36 months of records. Start keeping them from day one.
Staff training: Brief your kitchen team on the basics: what goes down the drain (water and small food particles only), what does not (oil, grease, food solids), and how to report a slow drain or potential overflow. A 15-minute orientation prevents expensive problems.
Trap monitoring schedule: Mark your calendar to visually check the trap depth one month after your first service. This tells you how quickly the trap fills under normal operating conditions.
See our guide on grease trap maintenance frequency to understand what a long-term service schedule looks like.
Frequently Asked Questions
Who inspects a new restaurant's grease trap before opening?
Typically two entities: the local building or plumbing department (code compliance inspection) and the local wastewater utility's FOG program (pretreatment compliance inspection). In some cities, these are combined into one inspection; in others, they are separate.
Does a health inspection include the grease trap?
Health inspectors focus on food safety, not wastewater pretreatment. Most do not check grease trap manifests or interceptor condition as a formal part of a health inspection. The grease trap is inspected by the wastewater utility's FOG program.
What happens if I fail the pre-opening grease trap inspection?
You will receive a correction notice listing the deficiencies. Once you make the corrections, you request a re-inspection. In most jurisdictions, you cannot receive a Certificate of Occupancy or a food service permit until both the plumbing and FOG inspections pass.
How do I find out what FOG program my city uses?
Contact your city's wastewater utility or public works department. Ask specifically for the industrial waste or pretreatment program. This is the office that administers FOG requirements for food service establishments.
Do I need a separate FOG permit, or is the plumbing permit sufficient?
Many cities require separate FOG program registration in addition to the plumbing permit. Check with both the building department (plumbing permit) and the wastewater utility (FOG registration) before scheduling inspections.
How long does the pre-opening grease trap inspection process take?
Scheduling varies by city. Some inspection offices can turn around an appointment within a few days; others have two-to-four-week wait times. Factor this into your restaurant opening timeline and schedule the inspection well before your target opening date.
Can I operate temporarily while waiting for the FOG inspection?
In most jurisdictions, no. A Certificate of Occupancy requires passed inspections, and operating without a CO is a code violation. Check with your city's permitting office for any temporary operating provisions that may apply in your specific situation.
Conclusion
The grease trap inspection is one of the last hurdles before a new restaurant can open, and one of the most avoidable sources of delay. Confirm the installation matches the permit, make sure all fixtures are connected and accessible, complete your FOG program registration, and have your BMP plan ready. Starting right means you will not be in a scramble the week before your planned opening. If you need a licensed grease trap installation contractor or service provider to help you prepare, find one at greasetraplocator.com.
Author: Grease Trap Locator Editorial Team
The Grease Trap Locator editorial team covers FOG compliance, grease trap maintenance, and commercial kitchen regulations across the US and Canada. Our guides are written for restaurant owners, facility managers, and food service operators who need practical, accurate information without the fluff.
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