Grease trap guide for first-year operators and paper

Last updated 2026-08-21

What is a grease trap?

A grease trap is a plumbing interceptor that slows kitchen wastewater so fats, oils, and grease float and food solids settle before the water leaves for the sewer. That is the device. That is the job.

Most field people say grease interceptor for the same hardware. Small indoor steel boxes are usually hydromechanical units. Large in-ground concrete tanks are gravity units. Same physics. Different detention time.

Cities care because cooled FOG sticks to sewer walls and can block the pipe. Federal pretreatment rules already hit this point. 40 CFR 403.5 prohibits "Solid or viscous pollutants in amounts which will cause obstruction to the flow in the POTW resulting in Interference." ^[1] That one sentence is what your city FOG ordinance sits on.

The International Plumbing Code requires interceptors so oil, grease, sand, and other harmful substances do not hit the building drain, the public sewer, a private sewage system, or the treatment plant. ^[2] EPA's food service FOG fact sheet puts the kitchen version in plain language: keep FOG out of the drain, dry-wipe pots, collect fryer oil, and maintain the interceptor. ^[5]

A grease trap is not a septic tank. It is not a garage oil separator. It does not make grease vanish. If nobody pumps the mat and the solids, you just own a sealed box of rancid FOG with a pipe through it.

The Clean Water Act pretreatment framework lives in 33 U.S.C. 1317, which is why a local sewer utility can write FOG rules that actually stick. ^[9] If you cook and you drain, you likely need a trap. Confirm with the plumbing inspector and the POTW, not with a salesperson.

How do you start grease trap work?

You start by picking a role, then you chase paper from the office that actually stamps it. There is no national grease trap license.

Kitchen operators install and maintain what the FOG ordinance and the plumbing code require. Installers pull plumbing permits and set tanks the inspector will pass. Haulers pump, manifest, and unload at a facility allowed to take FOG. Mix those roles up and you buy the wrong insurance and the wrong tank.

Week one, I'd make three calls. Pretreatment coordinator at the POTW. Plumbing inspector. State office that licenses septage or wastewater transporters if you plan to haul. Ask each for the current form list. Write down names. Confirm fees with them. Nobody honest can quote your city's fee from a national blog, and this page will not fake one.

The FDA Food Code, which many health departments adopt, does not by itself force a trap on every restaurant. It says, "If used, a grease trap shall be located to be easily accessible for cleaning." ^[3] Health wants access. The sewer utility wants FOG out of the main. Those are different desks.

Install work follows the plumbing code your state or city adopted, usually IPC Chapter 10 or UPC Chapter 10, plus local amendments. ^{[2] [8]} Hauling follows transporter and disposal rules. EPA's 2011 pretreatment program primer is the federal backdrop, not your permit. ^[4]

Skip the online national FOG certificate that never names your ordinance. Waste of money. I'd rather have a PDF of the city FOG rule and a named contact at the plant.

If you want a paper checklist in one binder, GreaseTrapPath sells a $199 one-time Interceptor + Manifest Kit at /start. This guide still works if you never buy it. The legal source is the board and the POTW.

Numeric local rules show up fast. Some states publish hard numbers. Massachusetts Title 5 is one published example of inspection and cleaning thresholds. Your city may use different numbers. Confirm them before you print a schedule.

Is a grease trap the same as a grease interceptor?

In the field, yes, people use both words for the FOG tank. In the code books, the words split by type and size. Use the word your inspector uses on the permit.

Hydromechanical grease interceptors (often the under-sink steel boxes) are rated in gallons per minute and grease capacity. Gravity grease interceptors are the big in-ground tanks, sized in gallons, with a long rest time so FOG floats. Grease recovery devices skim FOG automatically. Local approval still wins.

California's plumbing code puts grease interceptors in Chapter 10 and treats hydromechanical and gravity units as different animals. ^[7] The Uniform Plumbing Code does the same split in its Chapter 10. ^[8] Wisconsin's plumbing code requires interceptors and catch basins where harmful substances would otherwise enter the drain. ^[10]

I'd stop arguing vocabulary on the job site. Ask the inspector which listing they want (PDI, ASME, or a gravity tank on the local approval list) and buy that. A misnamed tank that fails inspection is still a failed tank.

Device	Typical place	How it holds FOG	Where the rule lives
Hydromechanical interceptor	Indoors, often under a sink	Baffles, short detention, gpm rating	IPC 1003, maker listing [2]
Gravity interceptor	Outdoors, in-ground	Long detention, gallon volume	UPC/CPC Chapter 10 [7] [8]
Grease recovery device	Indoors	Mechanical skim of FOG	Local approval plus listing

If a vendor says their additive turns a dish sink into a code interceptor, hang up. The code is about hardware, access, and pumping, not a bottle.

Who regulates grease traps, the city or the state?

Both, plus the feds in the background. The stack is federal pretreatment, then state plumbing and waste rules, then the city or county POTW that actually inspects you.

40 CFR Part 403 is the national pretreatment program. 40 CFR 403.3 defines the POTW and the interference idea your local FOG rule will repeat. ^{[14] [1]} EPA's 2011 primer describes the program as a federal, state, and local setup to protect treatment plants. ^[4] Your permit still comes from town.

State plumbing codes decide when an interceptor is required in the building drain. IPC Chapter 10 and UPC Chapter 10 are the two common books. ^{[2] [8]} California publishes its own plumbing code Chapter 10 on traps and interceptors. ^[7] Wisconsin publishes interceptor rules in SPS 382. ^[10] On-site systems can add another state layer. Massachusetts Title 5 is the classic example for grease traps on septic. ^[6]

The city sewer-use ordinance is what the inspector holds in their hand. Texas utilities lean on TCEQ FOG guidance and then write local limits. ^[11] Florida utilities run FOG programs under state water rules and local sewer-use rules. ^[12] I'd treat the POTW coordinator as the first human, then the state board if you haul waste across town lines.

If you work in California, read the grease trap board in california notes and still call the city. Same pattern in Florida: the grease trap board in florida page is a pointer, not a permit.

What paper do you need before you install or pump?

You need the paper your POTW and your state board name on their current list. There is no single federal grease trap form.

For an install: plumbing permit, site plan or fixture schedule if they ask, interceptor spec sheet the city accepts, and sometimes a pretreatment review before the building department signs. FDA Food Code 5-402.12 only cares that a used trap is easy to clean. ^[3] The plumber still needs the plumbing permit.

For a kitchen already built: FOG registration if the city has one, pumping contract or self-pump approval if they even allow that, and a log. Some cities want the hauler on an approved list. Confirm. Do not guess.

For a hauler: business registration, whatever waste transporter or septage license the state uses, a written place to discharge, vehicle and tank rules, and manifests. Opening a large outdoor vault can fall under OSHA confined space rules in 29 CFR 1910.146. Read that standard before anyone drops a ladder in. ^[13]

I'd put every approval in one folder with the ordinance stapled on top. Inspectors ask for the last pump ticket first. They do not ask for your motivational binder.

Fees, quotas, and processing times change. Confirm them with the board that cashes the check. Anyone publishing a national fee table for grease trap permits is making it up.

How often do you have to pump a grease trap?

You pump when your local rule says, usually at a grease-and-solids depth trigger, a calendar maximum, or both. There is no national pump interval.

Massachusetts Title 5 is a published, board-readable example for on-site grease traps. Under 310 CMR 15, you inspect monthly, and clean when grease hits 25% of effective depth or at least every three months, whichever comes first. ^[6] Many city sewer ordinances copy that 25% idea even when Title 5 does not apply.

Other cities use 25% of operating depth, a 90-day calendar, or a schedule the pretreatment office writes onto your permit. TCEQ's FOG materials tell Texas facilities to follow local cleaning and BMP rules, not a folk interval. ^[11] Florida's FOG program page pushes utilities to control FOG before it becomes a collection-system problem. ^[12]

I'd measure the mat, not the calendar alone. A fryer-heavy kitchen can blow past 25% in weeks. A coffee shop with almost no FOG might look empty at day 89 and still owe a pump if the permit is calendar-based.

Enzymes and bacteria as a substitute for pumping are a waste of money in most towns I would work. Lots of ordinances ignore them or ban them as the sole method. The inspector is counting inches of mat. Pump.

What belongs on a grease waste manifest?

A grease waste manifest is the chain-of-custody sheet from the trap to the disposal site. If you haul FOG and you cannot show where it went, you are the problem.

Typical fields (confirm the exact form locally) are generator name and address, interceptor location and size, date and volume pumped, hauler name and license number, vehicle ID, disposal facility name, and signatures. Some cities want pH or a statement that yellow grease was kept out of the brown-grease tank. Use their form, not a generic truck ticket you like better.

EPA pretreatment materials treat hauled waste and FOG as a plant-protection issue, not a paperwork hobby. ^{[4] [5]} State transporter rules and the receiving facility's permit decide what a legal load looks like. Texas FOG guidance and Florida utility FOG programs both push proper hauling and disposal instead of dumping. ^{[11] [12]}

Keep copies. The kitchen keeps a copy. The hauler keeps a copy. The plant keeps a copy. Retention periods are local. Confirm how many years the POTW wants. I would not toss a manifest because a blog said three years.

If a generator asks you to leave the gallons blank, walk. Blank gallons is how fake pump-outs start. Your name is on the line.

How do you size a grease trap so an inspector passes it?

You size it the way the adopted plumbing code and the local FOG ordinance tell you to size it. You do not size it from a Facebook chart.

IPC Chapter 10 points hydromechanical units at listed ratings and gravity units at the local design method. ^[2] UPC and the California Plumbing Code Chapter 10 have their own interceptor sizing paths, including gravity tanks sized for detention. ^{[8] [7]} Wisconsin SPS 382.34 is another state-specific interceptor chapter. ^[10] If two books conflict, the one your city adopted wins.

I'd call the inspector before I order a tank. Ask what listings they accept, whether an indoor hydromechanical unit is even allowed for that menu, and whether they want an outdoor gravity tank past a certain fixture load. Wrong tank hurts. A cheap under-sink box on a fryer line is how you fail the first inspection.

Menu matters more than seating folklore. High-FOG cooking (fryers, woks, rotisseries, meat roasting) loads an interceptor faster than a pastry case. Pretreatment staff know this. Bring a fixture list, not a vibe.

Manufacturer sizing charts are a starting point, not a variance. If the city publishes a worksheet, use the worksheet. If they require a licensed plumber's calculation, pay for that. I would not fight an inspector with a brochure.

What does first-year grease trap operations actually look like?

Year one is boring paper and a pump schedule you actually follow. It is not a brand story.

Kitchens: log every pump-out, keep manifests, dry-wipe, keep yellow grease in closed rendering containers, and do not pour fryer oil in the floor sink. Train night staff once, then check the log yourself. EPA's food service FOG sheet is still the right kitchen list. ^[5] If the city wants a quarterly report, put the due date on a wall calendar.

Haulers: route work, spill kit, confined-space sense on big vaults, and a disposal site that is open when you said it was. ^[13] First year is when people dump in the wrong plant because it was closer. Don't.

Installers: warranty callbacks on lids that pond water, and change-orders when the indoor unit the owner bought cannot pass local rules. Budget time to sit with pretreatment, more than the building department. ^{[2] [4]}

Nobody has a clean national data set on first-year pump prices or fail rates. Local quotes bounce. The closest honest method is three hauler bids plus the ordinance in your hand.

Access is not optional. FDA Food Code 5-402.12 is short because it only cares that the trap can be cleaned. ^[3] If you bury a unit under a deck with no manhole, you built a violation.

What is a waste of money in year one?

National certificates that do not name your ordinance. Enzyme programs sold as a pump replacement. Oversized gravity tanks for a low-FOG shop because a salesperson gets paid on gallons. Undersized under-sink boxes for a fryer line because they were in stock.

I'd also skip custom software in month one. A folder, a camera roll of tickets, and the city form beat a dashboard nobody opens. Buy software after you know which report the POTW actually wants.

Do buy: the listed interceptor the city already recognizes, lids that one person can open, and a hauler who will put gallons on the manifest. Do buy confined-space sense if you open vaults. ^[13]

Insurance amounts are local and job-specific. Confirm with your carrier and with any disposal site that names coverage on the gate sheet. This page will not invent a policy limit.

If a class will not show you the code section, it is entertainment. Read IPC or UPC Chapter 10 and your FOG ordinance instead. ^{[2] [8]}

How do you confirm grease trap board rules by state?

You confirm by reading the state plumbing or waste rule, then calling the city POTW anyway. State pages are not a substitute for the sewer-use ordinance.

Start with the adopted plumbing code chapter on interceptors, the state septage or FOG transporter license if you haul, and the local pretreatment contact. California is a plumbing-code state with a thick Chapter 10. ^[7] Florida runs FOG through utilities and DEP program materials. ^[12] Massachusetts on-site traps sit in Title 5. ^[6] Texas facilities still answer to the city, with TCEQ FOG guidance in the background. ^[11]

Use a state pointer, then verify. grease trap board in alabama, grease trap board in alaska is thin on people and heavy on local utilities, grease trap board in arizona, grease trap board in arkansas, grease trap board in colorado, grease trap board in connecticut, grease trap board in georgia, and grease trap board in idaho are starting points. They are not your permit.

Ask the board for the current form, the current fee, and whether a license is even required for your role. Then ask the POTW the same three questions. If the answers differ, the stricter desk is the one that can shut you down.

What happens if you skip pumping or fake a manifest?

You can clog the line, flood a kitchen, trip a sewer overflow, and pick up local enforcement. Federal pretreatment already treats obstruction as interference. ^[1] EPA's overflow materials exist because blocked sewers leave the pipe. ^{[4] [5]}

Local tools are the ones that land on you: notices, re-inspection fees, pumping at your expense, water shutoff in the worst FOG programs, and referral of haulers who invent gallons. Confirm penalties with the city. They change.

Faking a manifest is worse than missing a pump. The generator, the hauler, and the plant all signed a story. When the story is false, every name on it is in play. I would fire a driver who asked a kitchen to sign a blank ticket.

The fix path is dull. Pump now. Keep the ticket. Photograph the open tank if the city wants proof. Call pretreatment if you inherited a stone-full unit. Do not add enzymes and hope.

GreaseTrapPath is an independent publisher, not a law firm and not a service company. Confirm every form, fee, and interval with the board that signs it.

Frequently asked questions

What is grease trap?

A grease trap is an interceptor on a kitchen drain that slows wastewater so fats, oils, and grease float and solids settle. Clearer water then goes to the sewer. Inspectors often say grease interceptor for the same device. It only works if it is sized for the fixtures and pumped before the FOG mat fills it.

How do you start grease trap?

Pick a role first: kitchen operator, installer, or FOG hauler. Then collect paper from the local POTW and the plumbing or waste board that actually stamps permits. There is no national grease trap license. Confirm forms and fees locally. Do not buy a tank or a truck until those offices name what they want.

Do I need a federal grease trap license?

No. 40 CFR Part 403 sets pretreatment standards and prohibitions, including the obstruction rule in 403.5, but it does not issue a grease trap license to restaurants or haulers. Your plumbing permit, FOG registration, and any transporter license come from the state and the city POTW. Confirm with those desks.

Can I pump my own grease trap?

Only if the local FOG ordinance and the state waste rules allow it, and only if you have a legal disposal site. Many cities require a registered hauler and a manifest. Home-bucket pumping into a dumpster is how people get fined. Ask pretreatment in writing before you try it.

Is an under-sink unit enough for a restaurant?

Sometimes, if the adopted code and the city FOG rule allow a hydromechanical interceptor for that menu and flow. Fryer-heavy kitchens often get sent to an outdoor gravity tank. IPC and UPC Chapter 10 plus local amendments decide, not the unit on sale at the supply house. Ask the inspector before you order.

What is FOG in grease trap rules?

FOG means fats, oils, and grease from cooking. In a trap, FOG floats as a mat. In a sewer, it cools and can stick to the pipe. EPA food service FOG materials treat FOG as a clog and overflow problem. Keep fryer oil in rendering containers. Do not pour it in the sink.

How long can I wait between pump-outs?

Wait only as long as your local rule allows. A common published example is Massachusetts Title 5: clean at 25% of effective depth or at least every three months, whichever comes first. Other cities use 25% depth, a 90-day calendar, or a permit schedule. Confirm the number on your ordinance. Do not copy another state.

Do I need a plumber to install a grease trap?

Usually yes, because interceptor work sits in the plumbing code and needs a permit. IPC Chapter 10 and UPC Chapter 10 are the common books. Some small listed under-sink units still require a licensed plumber and an inspection. Confirm with the building department. Owner-install shortcuts fail when the lid cannot be opened for cleaning.

Where does the grease go after pumping?

To a facility permitted to take FOG or septage, on a manifest that names the generator, the gallons, the hauler, and the plant. It does not go in a storm drain, a dumpster, or a random manhole. Ask the receiving plant what they accept before you pump. Keep copies of the ticket.

Are enzymes a legal substitute for pumping?

Usually no, not as a stand-alone method. Many FOG ordinances ignore additives or ban them as a replacement for cleaning. The inspector measures the grease mat. I'd pump on the city's schedule even if a vendor swears the bacteria eat the FOG. Confirm any additive rule in the local ordinance.

What is a POTW and why does it matter?

POTW means publicly owned treatment works, defined in 40 CFR 403.3. It is the sewer plant and collection system. Pretreatment staff at the POTW write FOG rules so grease does not interfere with treatment. They are the people who inspect interceptors and read manifests. Get their name in week one.

Does the FDA Food Code require a grease trap?

Not by itself for every kitchen. FDA Food Code 2022 section 5-402.12 says that if a grease trap is used, it shall be located to be easily accessible for cleaning. Health departments that adopt the Food Code care about access. The requirement to have a trap usually comes from plumbing codes and the sewer utility.

Can opening a grease interceptor be a confined space job?

Yes, a large in-ground interceptor can meet OSHA's confined space conditions. 29 CFR 1910.146 covers permit-required confined spaces. Do not freelance the atmosphere or the entry. Read the standard, train the crew, and follow it. Under-sink boxes are a different animal, but vault entries are not casual.

Sources

1. eCFR 40 CFR § 403.5 National pretreatment standards: Prohibited discharges: Federal pretreatment rules prohibit solid or viscous pollutants in amounts which will cause obstruction to the flow in the POTW resulting in Interference.
2. ICC International Plumbing Code 2021 Chapter 10 Traps, Interceptors and Separators: IPC Chapter 10 requires interceptors and separators to prevent oil, grease, sand, and other harmful substances from discharging to the drain, sewer, or treatment plant.
3. FDA Food Code 2022, § 5-402.12 Grease Trap: FDA Food Code 2022 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 (2011): EPA describes the National Pretreatment Program as a federal, state, and local framework to protect POTWs from pollutants that interfere with treatment.
5. Massachusetts 310 CMR 15.00 Title 5 of the State Environmental Code: Massachusetts Title 5 requires on-site grease trap inspection and cleaning at 25% of effective depth or at least every three months, whichever is sooner, with monthly inspection.
6. California Plumbing Code 2022 Chapter 10 Traps and Interceptors: California Plumbing Code Chapter 10 sets state rules for traps and grease interceptors, including hydromechanical and gravity types.
7. IAPMO Uniform Plumbing Code 2021 Chapter 10 Traps and Interceptors: UPC Chapter 10 is a commonly adopted interceptor chapter that distinguishes grease interceptor types and sizing paths.
8. 33 U.S.C. § 1317 Pretreatment effluent standards (Clean Water Act): 33 U.S.C. 1317 authorizes federal pretreatment standards, which is the statutory backdrop for local FOG and interceptor programs.
9. Wisconsin SPS 382 Plumbing, § 382.34 Interceptors and catch basins: Wisconsin plumbing code requires interceptors and catch basins to keep harmful substances from entering the drain or sewer.
10. Florida DEP Domestic Wastewater and pretreatment program: Florida runs FOG control through utilities under state domestic wastewater and pretreatment rules and local sewer-use ordinances.
11. OSHA 29 CFR 1910.146 Permit-required confined spaces: OSHA 1910.146 governs permit-required confined space entry, which can apply when workers open large in-ground grease interceptor vaults.
12. eCFR 40 CFR § 403.3 Pretreatment definitions: 40 CFR 403.3 defines POTW, interference, and related pretreatment terms used in local grease trap programs.