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Grease Trap and Grease Interceptor Installation, Cleaning and Compliance in NYC

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A grease trap or grease interceptor is a plumbing device that
captures fats, oils, grease, food solids, and floating waste before they enter
the building drainage system or public sewer. In NYC, grease-generating
food-service businesses must install, operate, and maintain a properly sized
and designed device — because FOG (fats, oils, and grease) cools, hardens,
sticks to pipe walls, traps solids, and causes recurring backups, odors, and
sewer problems. This guide covers grease trap vs. interceptor, who needs one,
NYC Plumbing Code and DEP compliance, cleaning frequency, sizing, permits,
records, and when cleaning is not enough.
This article is general information, not legal or engineering advice;
confirm your specific requirements with a NYC Licensed Master Plumber.

Who needs grease control in NYC #

Grease traps and interceptors are essential for restaurants, commercial
kitchens, bars and cafes, bakeries, delis and supermarkets, schools and
cafeterias, hotels and banquet facilities, hospitals and nursing homes, food
trucks and commissaries, and mixed-use buildings where a ground-floor
restaurant can affect residential drains and the house sewer. Ordinary
residential kitchens in individual dwelling units generally do not require a
grease interceptor — but residents should still avoid pouring grease down
drains, which clogs kitchen lines and building drains.

Grease trap vs. grease interceptor #

Customers often use the terms interchangeably, but in practice they refer to
different sizes or installation types. A grease trap is
typically a smaller indoor device serving one or a few fixtures (e.g., under a
3-compartment or prep sink). A grease interceptor is a larger
device serving multiple fixtures or a heavier kitchen load, often
floor-mounted, in a basement, outside, or underground. Related equipment
includes automatic grease removal devices, solids interceptors, and waste-oil
rendering containers (storage, not fixture drainage). The correct device
depends on fixture flow, kitchen use, DEP and Plumbing Code requirements, space,
maintenance access, and food-operation type — a small under-sink trap may
not be enough for a high-volume restaurant.

Device types and where they are used #

  • Hydromechanical interceptor — indoor unit using flow control and separation; small restaurants, cafes, delis, bars, and retrofit spaces.
  • Gravity interceptor — larger, uses volume and retention time; often below grade for hotels, banquet and institutional kitchens, and high-flow operations.
  • Automatic grease removal device — mechanically removes accumulated grease; still requires inspection, cleaning, and maintenance.
  • Under-sink trap — smaller, easy to access, limited capacity, may need frequent cleaning.
  • Floor-mounted / recessed, or outdoor / underground interceptors — require safe service access and, for below-grade units, more formal design, excavation, and DOB/DEP coordination.
  • Multi-fixture and mixed-use installations — may serve pot, prep, and mop sinks and floor drains; in mixed-use buildings must protect both tenant piping and the shared building sewer.

Common grease problems and typical responses #

  • Kitchen sink backing up / slow sink → full trap or grease in the branch line; clean trap, snake/jet the line, review maintenance.
  • Trap overflowing or filling too fast → full, clogged outlet, or undersized device; pump/clean, inspect, and resize if needed.
  • Bad odor or pest issues → rotting solids or poor cleaning schedule; clean, seal, and adjust frequency.
  • Frequent restaurant backups → grease bypassing the trap, undersized device, or missing solids control; evaluate device, maintenance, and hydro-jetting.
  • DEP grease violation → missing, undersized, unmaintained, inaccessible, or noncompliant device; review compliance and correct.
  • Leaking trap or hard-to-open lid → cracked body, bad gasket, corrosion, or unsafe install; repair or replace and improve access.

NYC code, DEP, and permit requirements #

The 2022 NYC Construction Codes took effect November 7, 2022. NYC Plumbing Code
Chapter 10 covers traps, interceptors, and separators; Section 1003.3.1
requires a grease interceptor or automatic grease removal device to receive
drainage from fixtures and equipment with FOG waste in food-preparation areas,
and requires compliance with DEP. Devices should receive waste only from
FOG-producing fixtures, individual dwelling units generally do not require them,
access must be provided for service and inspection, and interceptors must be
maintained by periodic removal of grease, oil, floating substances, and solids.
DEP requires commercial grease-generating establishments to correctly install,
operate, and maintain properly sized devices, and commercial food waste
disposers are not allowed in NYC commercial establishments.
(2022 NYC Plumbing Code, Ch. 10)

Only licensed plumbers should install grease interceptors, and installation,
replacement, relocation, upsizing, or new connections can require DOB plumbing
permits and NYC Licensed Master Plumber supervision; routine cleaning or pumping of
an existing device usually does not. Businesses should keep cleaning/pumping
records, hauler receipts, service logs, and repair documentation on site, and
waste FOG and used cooking oil should be collected by a fat renderer or grease
recycler licensed by the NYC Business Integrity Commission.
(NYC DOB)

Frequently asked questions #

What is a grease trap? #

A grease trap is a plumbing device that captures fats, oils, grease, and food solids before they enter the drain system.

What is a grease interceptor? #

A grease interceptor does the same basic job as a grease trap, but the term is often used for larger or more formally designed devices serving commercial kitchens or multiple fixtures.

Is there a difference between a grease trap and a grease interceptor? #

In everyday conversation, people use the terms interchangeably. In design and code discussions, “interceptor” often refers to a larger or approved device sized for a specific commercial flow and grease load.

Who needs a grease trap or grease interceptor in NYC? #

Food-service and grease-generating commercial establishments generally need properly sized and maintained grease interception. This includes restaurants, cafes, bars, delis, bakeries, hotels, schools, hospitals, supermarkets, and commercial kitchens.

Do residential kitchens need grease traps? #

Individual dwelling units generally do not require grease interceptors. However, residents should still avoid pouring grease down drains because it can clog kitchen lines and building drains.

Why does NYC require grease interceptors? #

Grease can harden inside pipes and sewers, causing backups, odors, flooding, and sewer maintenance problems. Grease interceptors help keep FOG out of the sewer system.

Does DEP inspect grease traps? #

Yes. DEP checks businesses for grease interceptor installation and maintenance compliance.

Does DOHMH care about grease traps? #

Yes, especially for food-service establishments. Grease trap failures can create unsanitary conditions, odors, pests, wastewater backups, and food-service disruptions.

Does DOB get involved? #

Yes, when installation, replacement, relocation, sizing, or piping changes require plumbing permits, inspections, or NYC Licensed Master Plumber work.

Who can install a grease interceptor in NYC? #

Licensed plumbers should install grease interceptors. Installation often requires proper sizing, piping, venting, access, and code-compliant connection.

Do I need a permit to install a grease trap? #

Often, yes, especially for new installation, replacement with piping changes, relocation, upsizing, or commercial kitchen buildout work. Routine cleaning/pumping usually does not require a DOB permit.

How often should a grease trap be cleaned? #

It depends on size and grease volume. High-use restaurants may need frequent service. Low-volume cafes may need less frequent service. The right schedule should prevent the trap from becoming full, overflowing, or discharging grease downstream.

How do I know my grease trap is full? #

Signs include slow sinks, odors, grease floating near the lid, backups, overflow, pest issues, and grease buildup downstream.

Why does my restaurant drain keep backing up even after cleaning the grease trap? #

The downstream drain line may already be packed with grease, the interceptor may be undersized, the wrong fixtures may be connected, the device may be bypassed, or cleaning may not be frequent enough. Hydro-jetting and camera inspection may be needed.

Can hydro-jetting replace grease trap cleaning? #

No. Hydro-jetting cleans drain lines. Grease trap/interceptor cleaning removes grease and solids from the device. Both may be needed, but they solve different problems.

Can I pour fryer oil into a sink if I run hot water? #

No. Hot water may move grease farther down the line, but grease cools and hardens downstream. Fryer oil should be collected and disposed of or recycled properly.

Are garbage disposals allowed in NYC commercial kitchens? #

Commercial food waste disposers are not allowed in NYC commercial establishments.

What fixtures should connect to a grease interceptor? #

Fixtures that discharge fats, oils, or grease from food-preparation areas may need to connect. The exact layout should be designed and reviewed by qualified plumbing professionals.

Should a dishwasher connect to a grease interceptor? #

It depends on the approved design and code/DEP requirements. Temperature, flow, detergents, solids, and kitchen layout must be considered. Do not assume a dishwasher can be connected without design review.

What happens if a grease trap is too small? #

An undersized device may fill too quickly, let grease pass downstream, cause backups, create odors, and trigger DEP/DOHMH issues.

What records should a restaurant keep? #

Keep cleaning logs, pumping receipts, hauler information, repair records, device information, photos where useful, and DEP/DOHMH correspondence.

Who removes grease waste? #

Waste cooking oil and FOG should be collected and handled by appropriate licensed trade-waste or rendering companies.

Can grease cause sewer backups in apartments above a restaurant? #

Yes. In mixed-use buildings, grease from a commercial tenant can clog shared drains, the house trap, or building sewer and affect residential tenants.

What should I ask before approving grease trap or interceptor work? #

Useful questions to ask before approving the work:

  • Is this a grease trap, grease interceptor, or automatic grease removal device, and which fixtures discharge into it?
  • Is the device properly sized for the business and accessible for cleaning and inspection?
  • Are baffles, flow control, gaskets, and covers intact, and is the device being bypassed?
  • How often is it cleaned or pumped, and are cleaning records available?
  • Is the downstream line already grease-clogged, and is hydro-jetting or camera inspection needed?
  • Is replacement, upsizing, or relocation required, and is DOB filing or Licensed Master Plumber work required?
  • Has DEP or DOHMH issued a notice, and is waste grease being collected by a proper hauler?
  • Are employees trained not to pour grease or food solids down drains?

When grease trap cleaning is not enough #

Cleaning or pumping may not solve the problem when the device is undersized,
missing, bypassed, or has the wrong fixtures connected; when baffles or flow
control are broken or missing; when the outlet is clogged or the body/lid/gasket
is cracked or leaking; or when the device is inaccessible for maintenance. It
also falls short when the downstream drain line, building drain, or house trap
is already packed with grease, when grease has caused repeated sewer backups,
when grease-handling practices are poor, or when DEP or DOHMH has issued a notice
requiring correction. In those cases the fix is repair, replacement, upsizing,
hydro-jetting, camera inspection, or DOB-permitted plumbing work.

Sources #





clogs, hydro jetting, stoppages, water jetting
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