Do I Need a Grease Trap?
Answer 5 quick questions about your commercial kitchen to find out whether you're legally required to install a grease trap or interceptor — and what size requirement likely applies to your operation.
Get a Clear Answer Before You Call a Plumber
Not every food service operation requires a grease trap — but most do, and the consequences of operating without one when you're required to can include fines, mandatory retrofitting at your expense, and in some jurisdictions, suspension of your food service permit. The rules depend on your establishment type, the fixtures you operate, and the FOG ordinance in your municipality.
This decision tool walks through the key factors that determine grease trap requirements under US and Canadian FOG ordinances. It takes about 60 seconds. At the end, you'll get a clear recommendation — required, likely required, likely exempt, or needs local verification — along with the reasoning behind it and next steps.
Important: This tool reflects common requirements across major US and Canadian FOG ordinances. Requirements vary by municipality and province. Always confirm your specific obligation with your local sewer authority or building department before making installation decisions.
Find Out If You Need a Grease Trap
Answer each question about your operation — your recommendation appears at the end.
Your Result
Verdict
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Trap Type Likely Needed
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Reasoning
Recommended Next Steps
What Determines Whether You Need a Grease Trap
The threshold question under virtually every US and Canadian FOG ordinance is the same: does your operation generate fats, oils, and grease as part of food preparation or service, and does that wastewater discharge to the municipal sewer? If the answer to both is yes, a grease trap or interceptor is almost certainly required. The ordinance does not care whether you think your output is low — if you have a commercial dishwasher, a 3-compartment sink, and floor drains, the code applies.
Establishment type affects what kind of trap is required, not whether one is required. Full-service restaurants and institutional kitchens almost universally require an outdoor in-ground interceptor. Light prep operations like cafes and bakeries may qualify for a smaller passive under-sink trap in some jurisdictions. Fast food and high-volume operations often face stricter requirements — larger minimum capacities, more frequent inspection cycles.
Discharge destination is the other key variable. Operations on municipal sewer are subject to the local FOG ordinance — which has enforcement teeth including fines and permit suspension. Operations on private septic are not subject to the municipal FOG ordinance, but FOG discharge into a septic system damages the drain field and is covered by separate environmental regulations in most states and provinces. The answer to "do I need a grease trap" is essentially yes regardless of discharge type — the authority and consequences just differ.
New construction and renovations are the highest-risk situations for missing grease trap requirements. Building permit applications for food service spaces trigger FOG ordinance review in most jurisdictions. An approved building permit for a kitchen without a required grease trap creates a compliance problem that surfaces at food service permit application — expensive to retrofit after the slab is poured.
Grease Trap Requirements — Common Questions
Based on common US municipal FOG ordinances and Canadian provincial requirements.
Some jurisdictions exempt operations that meet all of these criteria: no cooking process that generates FOG (cold prep, beverage service only), no commercial dishwasher, no floor drains connected to sewer, and a hand-wash sink as the only plumbing fixture. Pure coffee shops that use only an espresso machine and a hand sink have been granted exemptions in some cities. However, exemptions are jurisdiction-specific and must be formally approved — you cannot self-declare an exemption. Contact your local sewer authority with your specific fixture list to request a written exemption determination.
Consequences escalate in three stages. First, if discovered during a routine FOG inspection or triggered by a sewer blockage complaint, you will receive a corrective action notice requiring installation within a specified timeframe — typically 60 to 180 days depending on the jurisdiction. Second, fines apply for each day of non-compliance after the notice period. Third, if installation is not completed, your food service permit can be suspended. The most expensive scenario is discovering the requirement during a renovation or sale — retrofitting an in-ground interceptor into an existing slab can cost $8,000 to $25,000 depending on access and site conditions.
Food trucks themselves typically hold wastewater in an on-board tank and do not discharge to sewer while operating. The grease trap requirement applies at the commissary kitchen — the licensed commercial kitchen where the truck prepares food, washes equipment, and dumps its grey water tank. If your commissary is a shared commercial kitchen, they likely already have a grease trap and you are covered under their permit. If you are opening a dedicated commissary space, the same FOG ordinance requirements apply as any commercial kitchen.
Grandfathering under FOG ordinances is uncommon and inconsistently applied. Most modern FOG ordinances have retroactive provisions that require all food service operations — regardless of when the building was built — to comply within a specified phase-in period, often 1 to 3 years from ordinance adoption. If your city adopted an active FOG program in the last 10 years, you are almost certainly not grandfathered. The safest step is to contact your local sewer authority with your address and establishment type and ask directly whether a grease trap is currently required — get the answer in writing.
Installation cost depends heavily on site conditions. A new exterior installation on a straightforward site (accessible location, no slab cutting required) for a 1,000-gallon interceptor typically runs $4,000 to $8,000 including the unit, excavation, plumbing connection, and permit. Retrofit installations that require cutting through an existing concrete slab or navigating tight access run $8,000 to $25,000. The unit itself (1,000-gallon precast concrete or fiberglass interceptor) costs $800 to $2,500 — the majority of the cost is labour and site work. Get three quotes from licensed contractors and confirm each quote includes the permit application and inspection coordination.
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