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Grease Trap Cleaning for Restaurants and Multi-Site Food Service

A grease trap that is not cleaned on time lets fats, oils and grease into the sewer, where they cause blockages, backups and fines. Facility First manages grease trap cleaning through vetted local providers, with measured intervals, hauler records and photo close-out for every location.

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What Grease Trap Cleaning Involves

Grease trap cleaning is the removal of fats, oils and grease (FOG) and settled food solids from the device that holds them back before kitchen wastewater reaches the sewer. The device works only while FOG has room to cool and separate in still water. As the grease and solids layers grow, that room shrinks and grease passes through.

There are two main types:

Hydromechanical grease interceptors (often called grease traps). Smaller units under a sink or in the floor, rated by flow and grease capacity. Portland’s Bureau of Environmental Services describes these as typically 20 to 50 gallons per minute.
Gravity grease interceptors. Large in-ground tanks outside the building, typically 1,000 to 4,000 gallons in Portland’s description, pumped by vacuum truck.

A thorough cleaning typically removes the grease cap, liquid and settled solids, scrapes the walls and baffles, and checks the inlet, outlet, flow control device and lid gaskets. Grease and solids depths are recorded before cleaning so the next interval rests on real measurements.

Codes, Standards and Requirements

Federal pretreatment rule. Under 40 CFR 403.5, a business may not discharge pollutants into a public sewer that cause interference, including “solid or viscous pollutants in amounts which will cause obstruction to the flow.” The EPA reports that grease is the most common cause (47 percent) of reported sewer blockages. Local sewer authorities enforce FOG control through ordinances, design requirements, inspections and penalties.

Plumbing code. The International Plumbing Code, Section 1003, requires interceptors to keep oil and grease out of the sewer, and requires grease interceptors where grease-laden waste is generated, such as restaurant kitchens. Installation must follow the manufacturer’s specifications. Many states and cities adopt the IPC with amendments, and the local plumbing official decides what applies.

Local FOG programs. Most cleaning rules are local. Two examples:

New York City. DEP rules require interceptors to be cleaned often enough that accumulated FOG and solids do not exceed 25 percent of the total liquid depth. Emulsifiers, enzymes, chemicals, microbial agents and other additives are prohibited in interceptors. Prefabricated units must be city-approved or tested to PDI G101 or ASME A112.14.3 or A112.14.4. DEP lists a maximum penalty of $10,000 per day, per violation.
Portland, Oregon. The city states that most interceptors need cleaning at 25 percent full of FOG and solids, though some high-efficiency hydromechanical units can hold up to 75 percent. A cleaning report must be filed after every cleaning, and additives are prohibited.

Each location’s sewer authority decides the cleaning standard, the reporting method and whether a fixed interval applies.

Preventive Maintenance Schedule for Grease Trap Cleaning

Grease traps fill at a rate set by menu, volume and kitchen habits, so a schedule built on measurements prevents missed cleanings and unnecessary pump-outs. The EPA notes that good FOG practices in the kitchen can reduce required maintenance, and a written schedule gives inspectors the record they ask for.

Task	Recommended frequency	Basis
Measure grease and solids depth	Weekly until a cleaning interval is establishedas recommended	City of Lawrence, Kansas FOG program guidance
Clean or pump out the interceptor	Before FOG and solids reach 25 percent of liquid depthor the manufacturer’s rated capacity if different	NYC DEP rules; Portland BES; manufacturer instructions
Inspect baffles, flow control device, vent and lid gaskets	At every cleaning	Facility First default
File a cleaning report with the local program	After every cleaningwhere required	Portland BES; local FOG program
Keep proof of used cooking oil (yellow grease) pickup	Every pickup; kept at least one year in New York City	NYC DEP rules
Check the downstream sample box or line for grease carryover	Quarterly	Facility First default
Review interceptor sizing when the menu, fixtures or hours change	At each change	Facility First default
Refresh kitchen staff on scraping plates and keeping grease out of drains	At onboarding and annually	Facility First default

Facility First default is the starting interval in each program, adjusted for each site.

The sewer authority, the manufacturer and the property’s insurer can require more frequent service. Each location’s schedule is set in its program and recorded on every visit.

Signs a Grease Trap Needs Cleaning

Slow drains at prep sinks or floor drains
Grease or sewage odors in the kitchen or near the outdoor lid
A grease layer approaching the 25 percent mark at the last measurement
Grease visible in the downstream sample box or manhole
A notice from the sewer authority or a failed inspection

Grease buildup in the lines may also need commercial drain cleaning.

Records to Keep

For each location, keep:

The interceptor type, size, rating and manufacturer manual
Each measurement of grease and solids depth, with the date
Each cleaning: date, provider, volume removed and the disposal receipt or manifest
Photos of the emptied interceptor and the condition of baffles and lid
Cleaning reports filed with the local program, where required
Proof of each used cooking oil pickup
Inspection reports, notices and the corrective action taken

The City of Lawrence, Kansas asks for maintenance logs to be kept three years. Retention periods differ by city.

How Facility First Runs Grease Trap Cleaning Across a Portfolio

Facility First does not pump grease traps itself. It manages the work through vetted local providers holding the permits and insurance each market requires.

Baseline. Each interceptor is listed with type, size and access notes, and the local FOG rules are attached to the location record.
Schedule. Cleanings are scheduled from measured fill rates and the local standard, then adjusted as records build up.
Dispatch. The work order goes to a provider in the location’s market. Where the city keeps a list of registered or preferred pumpers, the provider is selected from it.
Close-out. The provider records depths before cleaning, photographs the emptied unit and uploads the disposal receipt.
Verification and invoice. The record is checked against the work order and invoiced in one format. Client approval limits decide which repairs, such as a cracked baffle or damaged lid, proceed and which are quoted first.

Requests and records run on PostControl, so a location’s full cleaning history is available when an inspector asks. See work order management.

What Affects the Cost of Grease Trap Cleaning

Interceptor type and capacity
Location: under a sink, in a kitchen floor, or in a parking lot
Access, including equipment to move and heavy lids
Cleaning frequency and the amount of solids
Disposal fees at the receiving facility
After-hours scheduling
Line jetting or camera inspection of the outlet
Repairs to baffles, lids, gaskets or flow control devices

Grease Trap Cleaning for Restaurants, Retail and Offices

Restaurants. Cleaning is scheduled outside service hours, and indoor units near food prep are cleaned with floors and surfaces protected. Dishwasher connections are a common inspection issue: New York City requires dishwashers that use chemical sanitizers to drain to a grease interceptor, while EPA guidance cautions against sending high-temperature dishwasher discharge to a grease trap. The local plumbing official decides what is allowed.

Grocery, convenience and food halls. Delis, bakeries and hot food counters often share one interceptor, so the schedule follows the heaviest user and the lease states who arranges cleaning.

Offices and corporate campuses. Cafeterias and catering kitchens follow the same local rules as restaurants, scheduled around building hours and dock access.

Locations that also need backflow testing or commercial water heater repair can have that work scheduled on the same program.

Frequently Asked Questions

How Often Should a Grease Trap Be Cleaned?

Many local programs require cleaning before grease and solids reach 25 percent of the liquid depth, and some set fixed intervals. The right interval for each location comes from regular measurements and the local rule.

What Is the Difference Between a Grease Trap and a Grease Interceptor?

A grease trap usually means a smaller hydromechanical unit inside the kitchen. A gravity grease interceptor is a large in-ground tank, usually outside, that is pumped by a vacuum truck.

Can Enzymes or Bacteria Replace Pumping?

No. New York City and Portland both prohibit enzymes and other additives in grease interceptors. Portland notes that additives can let grease pass into the sewer or re-form into solids that obstruct pipes.

What Records Does a Sewer Inspector Ask For?

Typically the cleaning log with dates and depths, hauler receipts and, where required, cleaning reports filed with the city. Some cities also check used cooking oil pickup records.

Who Can Clean a Grease Trap?

A provider that meets the local program’s rules, which may include hauler registration or a preferred pumper list. Installation and replacement are plumbing work that may require a licensed plumber.

Sources

Put grease trap cleaning on one schedule and one record across every location.