Grease trap guide 72 for people starting the paper path

Last updated 2026-08-21

What is a grease trap?

A grease trap is a tank that slows kitchen wastewater so fats, oils, and grease (FOG) float and food solids drop, instead of coating the building drain or the public sewer. Codes also call the same family of devices grease interceptors and separators. If you cook, fry, or wash dishes for the public, you are in this world whether you like the name or not.

People mix up the words. In the field, "trap" often means a small hydromechanical unit under a sink, rated in gallons per minute. "Interceptor" often means a big in-ground gravity tank, rated in gallons. Both do the same job. They hold FOG long enough that it can be scooped, pumped, and hauled. They do not treat sewage. They do not make FOG vanish.

The International Plumbing Code states the duty in plain language. "Interceptors and separators shall be provided to prevent the discharge of oil, grease, sand and other substances harmful or hazardous to the building drainage system, the public sewer, the private sewage disposal system or the sewage treatment plant or processes." That is IPC 2021, Section 1003.1. ^[2]

Federal pretreatment rules sit behind the local FOG program. 40 CFR 403.5(b)(3) says you may not introduce "solid or viscous pollutants in amounts which will cause obstruction to the flow in the POTW resulting in interference." Kitchen grease is the classic viscous pollutant. ^[1]

The FDA Food Code does not size the tank. It only cares that, if you use one, you can clean it. "If used, a grease trap shall be located to be easily accessible for cleaning." That is Food Code 2022, Section 5-402.12. ^[3]

I treat "grease trap" as the whole stack. The device. The pumping. The manifest. The local FOG permit. If you only buy a box under the sink and ignore paper, you do not have a trap program. You have a future backup.

How do you start grease trap?

You start by picking a lane, then you collect the credentials that actually exist in that lane. There is no national grease trap exam and no federal operator card for restaurant interceptors. Anyone selling you that story is selling a myth.

Lane one is the food facility. You need a plumbing permit for the interceptor, often a FOG or pretreatment permit from the sewer utility, and a pumping contract with a hauler the POTW will recognize. Health review looks at access and cleanliness. The sewer side looks at FOG. They are not the same desk.

Lane two is the hauler. You need the state waste-transporter or septage credential your environmental agency actually issues, a legal disposal outlet that will take brown grease, vehicle and insurance that match the load, and whatever local FOG contractor registration the city wrote into its ordinance. I would not buy a vacuum truck until the outlet letter and the transporter paper are real. Trucks are easy to finance. Disposal capacity is not.

Lane three is the plumber or installer. That is a contractor license plus the interceptor listing (PDI G101 or ASME A112.14.3 for hydromechanical units, gravity tanks per the adopted plumbing code). ^[2]

Write the path down before you spend. Confirm each step with the board that owns it. Processing times move. Fees move. I will not invent either.

If you are choosing this work against other trades, read grease trap vs nearby career before you bet a truck payment on a route that only looks busy on Instagram.

First moves I would actually make. Call the POTW pretreatment or FOG desk and ask who may pump, what manifest they want, and where brown grease can go. Call the state waste program and ask the exact transporter license name. Call building for interceptor permits. Then price insurance and confined-space practice. Paper first. Steel second.

Is there a national grease trap license?

No. The United States does not issue a national grease trap license for restaurants or for FOG haulers. Pretreatment is a federal framework. The permit in your hand is local or state.

EPA's Introduction to the National Pretreatment Program (EPA-833-B-11-001) explains the split. EPA sets the national pretreatment standards in 40 CFR 403. The control authority is usually the publicly owned treatment works (POTW) with an approved program, or the state. ^[4] 40 CFR 403.3 is where the definitions live, including POTW, interference, and pass through. ^[5]

So you will see a tangle of names. FOG permit. Wastewater discharge permit. Interceptor registration. Liquid-waste hauler license. Septage transporter. None of those is a national card. Do not collect certificates from random online courses and call them licensing. A course can teach you. It cannot stamp a board file.

California sewer agencies operate under a statewide sanitary sewer systems order that pushed FOG control into sewer system management plans when FOG is part of the overflow problem. That is State Water Resources Control Board Order 2006-0003-DWQ (later reissued). It binds the sewer agency. It does not hand you a personal grease-trap license. ^[6]

If a salesperson says "the EPA license," hang up. Read grease trap guide 12 if you want the comparison version of that same warning.

Confirm the exact credential name with the board. Ask them to email the statute or ordinance section. If they cannot point to a section, you do not have a requirement. You have a rumor.

What paper do you actually need in year one?

Year-one paper is boring and it is the job. For a restaurant, the stack is usually the plumbing permit, as-built or manufacturer sizing sheet, the FOG or pretreatment registration, pumping invoices, and a log the inspector can read in two minutes. For a hauler, it is the transporter license, vehicle list, disposal facility agreement, trip tickets or manifests, and training records for confined space.

The FDA Food Code still wants that trap reachable for cleaning. Inspectors notice lids buried under mixers. ^[3] Sewer inspectors notice missing pump-outs more than they notice your logo.

I keep hauler paper in three folders. License. Outlet. Tickets. If a ticket does not name the generator, the date, the gallons, and the receiving facility, it is a napkin. Some cities want their own form. Use theirs. Do not argue about your prettier PDF.

GreaseTrapPath publishes this as a reference, not as a filing service. If you want a single packet of interceptor and manifest templates to mark up against local rules, the $199 one-time Interceptor + Manifest Kit is the /start page. It does not replace a board filing. Nothing we publish does.

Do not expect a national retention period. Some POTWs want two years of pump logs on site. Some want three. Confirm it. I would keep digital copies longer than the ordinance because an overflow investigation is not the moment you want to rebuild a route from memory.

First-year mistake I see is mixing yellow grease (fryer oil, rendered, sold) with brown grease (interceptor contents). Different outlets. Different paper. Different smell. Keep them apart on the truck and on the ticket.

If your city has a FOG contractor list, get on it before you sell accounts. Being good at pumping does not matter if the utility will not accept your tickets. For more paper-path comparisons in this series, see grease trap guide 18.

Who regulates grease traps, interceptors, and FOG waste?

Several desks, none of them eager to coordinate for you. Plumbing code officials own installation and listing. The health department owns food-facility access and sanitation. The POTW or state pretreatment program owns what may enter the sewer. The state environmental agency owns hauling and disposal. OSHA owns how you enter a tank. DOT owns the truck if you cross the commercial-motor-vehicle line.

40 CFR 403.5 is the federal prohibition on viscous pollutants that obstruct a POTW. ^[1] EPA's pretreatment introduction is the map of who enforces that prohibition. ^[4] Local FOG ordinances are where pump frequencies, 25 percent rules, and kitchen BMPs actually show up. Those ordinances are not in 40 CFR. You have to read them.

On-site systems are another planet. Massachusetts 310 CMR 15.230 requires grease traps for kitchen flows at restaurants and similar facilities that use Title 5 systems, with construction and capacity rules in that section. That is MassDEP, not your city FOG coordinator. ^[7] If the building is on a septic tank, do not copy a sewer-city pump schedule and call it done.

Model codes diverge. IPC Chapter 10 is the interceptor chapter many states adopt through the International Plumbing Code. ^[2] California publishes interceptor rules in the California Plumbing Code, Chapter 10. ^[8] Washington adopts the Uniform Plumbing Code through WAC 51-56. ^[9] Florida puts interceptors in the Florida Building Code, Plumbing, Chapter 10. ^[10] Same job. Different section numbers. Read the book your permit desk stamps.

I would call pretreatment first if the building is on a public sewer, and the on-site program first if it is not. That one phone call saves a wrong tank.

How is a grease trap sized, and which code wins?

Sizing is local, and the adopted plumbing code wins over a catalog page. Hydromechanical interceptors are commonly rated in gpm under PDI G101 or ASME A112.14.3, which IPC 2021 Chapter 10 points you toward for that class of unit. ^[2] Gravity interceptors are sized in gallons and detention, with minimums that change by code edition and by city amendment.

I do not trust a 20 gpm box under a fryer line in a full-service restaurant. It will pass a remodel inspection and fail a FOG inspection six months later. Outdoor gravity tanks are what most sewer departments actually want when the menu is heavy. Small coffee shops with no fryers are a different animal. Size to the fixtures and the menu, not to the cheapest lid.

Massachusetts Title 5 is stricter on septic-side kitchen flows. 310 CMR 15.230 sets grease-trap rules including capacity language you need to read in the current CMR, not in a blog. Confirm the gallons with MassDEP or the local Board of Health before you bury a tank. ^[7]

Manufacturers will run a fixture-unit worksheet. Use it. Then ask the POTW if they override it. Many FOG programs do. A worksheet that ignores the utility's minimum is a pretty way to fail plan check.

Nobody has a clean national dataset that says "this gpm prevents overflows." EPA's 2004 Report to Congress estimated 23,000 to 75,000 sanitary sewer overflows a year and 3 to 10 billion gallons discharged, with blockages a leading pathway. ^[11] That is why utilities care. It is not a sizing formula.

If you want a side-by-side of common setup choices, grease trap guide 24 is the next click I would make.

How often do you pump a trap, and what goes on the manifest?

Pump frequency is not in the Food Code and it is not a single EPA number. Local FOG ordinances set it. Many use a calendar (often 90 days as a starting point) or a 25 percent rule (pump when grease and solids take more than about a quarter of the wetted depth). I have not seen good national data that proves one interval. The closest honest statement is that utilities write a number, then shorten it when interceptors come in loaded or when they can tie FOG to a blockage. Confirm the rule your POTW printed.

EPA's food-service FOG fact sheet (EPA-833-F-12-003) treats food service establishments as a significant FOG source and pushes BMPs plus interceptor maintenance rather than magic additives. ^[12] Dry-wipe. Collect fryer oil as yellow grease. Pump the interceptor. That still works.

A usable manifest names the generator address, date, gallons or percent full, trap ID if the city uses one, hauler name and credential, and the receiving facility. Gallons matter. "Pumped" with no volume is how routes get sloppy.

I would photograph the open interceptor before and after on the first few accounts until you trust the crew. Photos settle arguments. They also teach you which kitchens lie about their last service.

Do not dump interceptor contents in a dumpster, a storm drain, or a field. That is not a gray area. It is how you lose the transporter license you just got.

If the receiving plant changes hours or stops taking brown grease, your whole route changes that afternoon. Keep a backup outlet on paper, not in your head.

Indoor hydromechanical trap or outdoor gravity interceptor?

Use the table, then ignore it if the POTW already told you what they will approve.

Piece	Hydromechanical (often called a trap)	Gravity interceptor
Location	Usually indoors, near the sink	Usually outdoors, in ground
How it is rated	GPM, PDI G101 or ASME A112.14.3 [2]	Gallons and detention, per adopted code
Typical user	Small kitchens, remodels	Full-service restaurants, FOG programs
Failure I see	Undersized, skipped pump-outs	Buried lids, illegal bypass pipes
Paper	Still needs pumping logs	Still needs pumping logs

Indoor units are easier to install in a finished kitchen. They are also easier to ignore. Outdoor tanks cost more dirt work and they are what many FOG inspectors can actually dip.

I would not fight a utility that requires gravity interceptors for food service. You will lose, and you will lose after the plumber is paid. Ask during plan check, not after the floor is tiled.

Bypass pipes around an interceptor are a favorite cheat and a favorite finding. Do not install one. Do not agree to "temporary" ones.

Access is a code issue, not a nice-to-have. Food Code 5-402.12 wants the trap easy to clean. ^[3] A gravity tank with a planter on the lid is a failed inspection waiting for a clipboard.

For another pass at equipment choices, grease trap guide 30 is in this same series.

What does first-year operations actually look like?

Messy. Routes slip. Kitchens close without telling you. One account will try to pay you to "just add enzymes this month." Say no.

If you own the restaurant, year one is a pumping calendar on the wall, a shared inbox for invoices, and someone who can open the lid without moving the mixer. If FOG staff do surprise dip tests, your log should match the tank. If it does not, you will buy a shorter interval.

If you haul, year one is account density, dump-window discipline, and not taking every restaurant 80 miles out. Deadhead kills this work. So does a single disposal plant with Saturday hours that exist only on their website.

Safety is operations, not a poster. Interceptors can meet OSHA's permit-required confined space definition when someone goes in. 29 CFR 1910.146 is the standard. ^[13] Hydrogen sulfide is in the air-contaminants tables. You do not need a dramatic story. You need a rule that nobody enters a tank without the program. ^[14]

I would spend more in year one on a second disposal option and on training than on wrap for the truck. Wrap does not pump a 1,000-gallon interceptor.

Keep the yellow-grease barrel and the brown-grease tank separate. Mixing them can lose both outlets.

Compare first-year patterns with grease trap guide 66 if you like seeing the same questions asked in a different order.

What is a waste of money when you are starting?

A vacuum truck with no outlet letter. National "certification" that no board recognizes. Enzyme subscriptions sold as a substitute for pumping. Undersized indoor units on a fryer-heavy menu. Custom software before you have 30 accounts.

Enzymes and bacteria products get marketed as a way to skip pumping. EPA's FOG fact sheet is about interceptors and BMPs, not about skipping the pump. ^[12] Plenty of POTWs restrict or ban additives because they can push FOG down the line as a liquid and drop it in the main. If your utility bans them, that is the whole analysis.

I would also skip fancy stainless lids until the city tells you the traffic rating they want. Buy the lid the inspector will accept. Not the one that photographs well.

Insurance shopping is not a waste. Operating without a transporter credential is. Confirm both. I will not quote a premium. Those numbers rot fast and they are not board-confirmable from a national article.

Training that ends in a card your state actually lists is worth it. Random online badges are not.

If a vendor promises approval timelines, they are inventing them. Boards do not work on vendor clocks.

Do you need confined space rules to work on grease traps?

If a person puts their body into the interceptor, you are in OSHA's world. 29 CFR 1910.146 covers permit-required confined spaces. Many in-ground grease interceptors check the boxes: limited entry, not designed for continuous occupancy, and a real atmospheric hazard. ^[13]

Hydrogen sulfide shows up in decomposing FOG. OSHA's Table Z-2 lists H2S exposure limits. ^[14] You do not guess the air. You test it. Pumping from the surface with a vacuum hose is a different exposure than climbing in to chip walls. Write that difference into the work plan so a new hire does not improvise.

I would treat "never enter" as the default for a new hauler. Most cleaning can be done from grade if the baffles and lids were installed for access. If a tank has to be entered, it is a confined-space job with the full program, not a hero moment.

Restaurant staff should not climb in. Ever. That is how a maintenance shortcut becomes an ambulance.

Confirm whether your state OSHA plan follows 1910.146 as written or with state amendments. The number stays the same. The extra state rules do not.

How do local FOG programs change the job?

They are the real boss. A FOG program can require interceptor registration, set pump intervals, ban garbage disposals, demand kitchen BMPs, and list approved haulers. That is on top of the plumbing code.

EPA built pretreatment so POTWs could protect treatment plants and collection systems from interference. ^[4] Local limits and FOG rules are how a city turns 40 CFR 403.5 into a kitchen inspection. ^[1] California's statewide sewer order pushed agencies to include FOG control in management plans when FOG contributes to overflows. ^[6] Your city may have copied that structure even if you are not in California.

Some programs are sleepy until a backup hits a river. Then they are not sleepy. Keep tickets like someone will ask next week.

I would read the FOG ordinance before I bid a restaurant install. If they require a 1000-gallon gravity tank and sample ports, your 25 gpm indoor quote is a gift to a competitor who can read.

Sewer overflows are why this exists. EPA's 2004 Report to Congress put national SSO events in a range of 23,000 to 75,000 per year and volume at 3 to 10 billion gallons. ^[11] FOG is not the only cause. It is a cause utilities can regulate at the kitchen.

For the next numbered pass in this series, grease trap guide 78 keeps the same stubborn focus on paper.

What should you confirm with the board before you spend?

Confirm the credential name, the statute or ordinance section, the current fee, and whether your disposal site is still authorized for brown grease. Confirm interceptor type the POTW will accept. Confirm who signs the manifest. Confirm confined-space expectations if anyone enters a tank.

I would not trust a Facebook group for those answers. Call the board. Get an email. Save the PDF of the ordinance.

Variable facts (fees, quotas, processing times) change. We do not invent them here. GreaseTrapPath is an independent publisher, not a law firm and not a pumping company. No approval and no timing guarantee. If you still want the kit after you have the ordinance in hand, it is the $199 Interceptor + Manifest Kit at /start.

Then do the unglamorous thing. Size to the code that is adopted, not the code you wish were adopted. Pump on the interval that is written. Keep tickets that a stranger can read. That is the whole paper path.

Frequently asked questions

What is grease trap?

A grease trap is a plumbing interceptor that slows kitchen wastewater so fats, oils, and grease float and solids settle, instead of coating sewer pipes. Codes also say grease interceptor or separator. Small indoor units are often rated in gpm. Large outdoor tanks are rated in gallons. Both still need pumping and paper.

How do you start grease trap?

Pick a lane first: restaurant owner, hauler, or installer. There is no national license. Confirm plumbing permits, POTW FOG rules, and any state waste-transporter credential with the boards that issue them. Get a real disposal outlet before you buy a truck. Keep manifests from day one. Fees and wait times are local.

Is a grease trap the same as a grease interceptor?

In the field, trap often means a small hydromechanical unit under a sink. Interceptor often means a large in-ground gravity tank. Plumbing codes group them as interceptors and separators. Inspectors may use either word. Ask which listing they want (gpm listing versus gallon tank) rather than arguing about the nickname.

Do restaurants need a grease trap by federal law?

There is no federal statute that says every restaurant must install a named grease trap. 40 CFR 403.5 does prohibit viscous pollutants that obstruct a POTW. Local plumbing codes and FOG ordinances are what actually require the device. The FDA Food Code only says that if you use a trap, it must be easy to clean.

Who issues the pumping manifest?

Usually the hauler generates the ticket, the generator keeps a copy, and the receiving facility signs for the load. Some cities mandate their own form. There is no single federal grease-trap manifest. Confirm the fields your POTW and state transporter program want: address, date, gallons, hauler credential, and outlet.

Can I start pumping traps without a state hauler license?

In most states, liquid-waste or septage transporter rules cover brown grease on a truck. Do not assume kitchen grease is unregulated because it is not a listed hazardous waste. Confirm the exact license name with the state environmental agency and with the city FOG desk. Operating on a rumor is how routes get shut down.

How often should a grease trap be cleaned?

Follow the written FOG ordinance, not a vendor calendar. Many cities use about 90 days or a 25 percent depth rule. Nobody has strong national data that one interval always prevents overflows. If dip tests show a loaded tank, the utility will shorten the interval. Confirm the number your POTW printed.

What size grease trap do I need?

Size to the adopted plumbing code and to any POTW minimum, using fixture flow and menu. Hydromechanical units are rated in gpm under standards IPC Chapter 10 points to. Gravity tanks are rated in gallons. I would not pick a 20 gpm indoor unit for a fryer-heavy restaurant just because it fits the cabinet.

Is grease trap waste hazardous waste?

Straight FOG from a kitchen interceptor is usually handled as special or liquid waste, not as a listed hazardous waste, unless it is mixed with solvents or other regulated material. That is not permission to dump it. State transporter and disposal rules still apply. Do not mix it with yellow grease or shop chemicals.

Do I need confined space training to pump a trap?

If work stays at grade with a vacuum hose, you still need splash, atmosphere, and traffic sense. If anyone enters the tank, 29 CFR 1910.146 can apply. Hydrogen sulfide is a real atmospheric hazard in FOG tanks. Default for a new crew should be no entry. Confirm your state OSHA plan before you write the procedure.

What is the difference between yellow grease and brown grease?

Yellow grease is used cooking oil collected from fryers, usually rendered and sold. Brown grease is what comes out of the interceptor, mixed with water and solids. Different outlets, different tickets, different odor. Mixing them can lose both buyers. Keep barrels and tanks separate on the truck and on the paper.

How much does a grease interceptor installation cost?

There is no honest national price. Indoor hydromechanical units can be a modest plumbing change. Outdoor gravity tanks are dominated by excavation, traffic lids, and site restoration. Quotes move with soil, groundwater, and whether the POTW demands a sample port. Get two local bids after plan check, not before.

Does the health department or the sewer utility inspect traps?

Often both, for different reasons. Health staff care that the trap is reachable and not a sanitation mess, which tracks Food Code 5-402.12. Sewer or pretreatment staff care about FOG load, pump interval, and illegal bypasses. A pass from one desk is not a pass from the other. Keep both numbers in the log.

Can I use enzymes instead of pumping?

I would not. Many POTWs restrict additives because they can send FOG downstream. EPA's food-service FOG guidance is built on interceptors, BMPs, and maintenance, not on skipping pump-outs. If your ordinance bans additives, that is the answer. If it is silent, pumping still has to happen on the written interval.

Sources

1. eCFR, 40 CFR 403.5 National pretreatment standards: Prohibited discharges: 40 CFR 403.5(b)(3) prohibits introducing solid or viscous pollutants in amounts that will cause obstruction to flow in a POTW resulting in interference.
2. ICC, International Plumbing Code 2021 Chapter 10 Traps, Interceptors and Separators: IPC 2021 Section 1003.1 requires interceptors and separators to prevent oil and grease from reaching the building drain, public sewer, or treatment plant, and Chapter 10 references hydromechanical listing standards.
3. U.S. FDA, Food Code 2022: FDA Food Code 2022 Section 5-402.12 states that if used, a grease trap shall be located to be easily accessible for cleaning.
4. U.S. EPA, Introduction to the National Pretreatment Program (EPA-833-B-11-001): EPA's 2011 pretreatment introduction describes 40 CFR 403 as the national framework, with the POTW or state acting as control authority.
5. eCFR, 40 CFR 403.3 Definitions: 40 CFR 403.3 defines POTW, interference, pass through, and related pretreatment terms used in FOG enforcement.
6. California State Water Resources Control Board, Order 2006-0003-DWQ Statewide General WDR for Sanitary Sewer Systems: The statewide sanitary sewer systems WDR required sewer system management plans, including FOG control where FOG contributes to overflows.
7. Massachusetts, 310 CMR 15 Title 5 of the State Environmental Code: 310 CMR 15.230 requires grease traps for kitchen flows at restaurants and similar facilities using on-site sewage systems and sets construction and capacity rules.
8. ICC, California Plumbing Code 2022 Chapter 10 Traps, Interceptors and Separators: The California Plumbing Code Chapter 10 is the adopted interceptor chapter used in California plan check.
9. Washington State Legislature, WAC 51-56 State Building Code adoption of the Uniform Plumbing Code: WAC 51-56 adopts the Uniform Plumbing Code with Washington amendments, which is the plumbing-code path for interceptors in that state.
10. ICC, Florida Building Code, Plumbing, 2020 Chapter 10 Traps, Interceptors and Separators: Florida Building Code, Plumbing, Chapter 10 is the interceptor chapter used in Florida permitting.
11. U.S. EPA, Report to Congress: Impacts and Control of CSOs and SSOs (EPA 833-R-04-001, 2004): EPA estimated 23,000 to 75,000 sanitary sewer overflows per year in the United States, discharging about 3 to 10 billion gallons.
12. OSHA, 29 CFR 1910.146 Permit-required confined spaces: 29 CFR 1910.146 sets the federal standard for permit-required confined spaces, which can apply when a worker enters an in-ground interceptor.
13. OSHA, 29 CFR 1910.1000 Table Z-2 air contaminants: OSHA Table Z-2 lists hydrogen sulfide exposure limits relevant to atmospheres over decomposing FOG.