Grease Trap Requirements Ottawa: Cost, Sizing and Permits for Restaurants in 2026

If your Ottawa space cooks, processes or prepares food, you need a grease trap. It is not optional and it is not a City preference. The Ontario Building Code requires a properly sized, properly installed and properly maintained grease interceptor anywhere food is cooked, processed or prepared, and the City of Ottawa Sewer Use By-law limits what grease can go down your drain and backs that up with penalties and fines. Grease trap and grease interceptor are the same piece of equipment in everyday use, and the City itself uses both words, so do not let the wording throw you. The real questions are not whether you need one. They are how big it has to be, where it goes, what the permit costs and how often it has to be cleaned. 

Do you need a grease trap for a restaurant in Ottawa?

Yes. The City is direct about it in its own guidance for restaurant owners: grease traps are required under the Ontario Building Code anywhere food is cooked, processed or prepared, and they have to be properly sized, installed and maintained. The City's Install and Maintain a Grease Trap handout is the short version worth printing for your kitchen wall.

Two separate rulebooks apply and people mix them up constantly. The Ontario Building Code governs the interceptor itself, whether it is required, how it is sized and how it is installed. The City of Ottawa Sewer Use By-law, No. 2025-94  governs what actually leaves your building and goes into the City sewer. You can pass a building inspection and still be offside the Sewer Use By-law later if the unit never gets serviced.

Worth knowing that the Sewer Use By-law number changed. By-law 2025-94 replaced the old 2003-514. If you are working from an older checklist or an old consultant report that cites 2003-514, that reference is stale.

Does a cafe need a grease trap too?

Usually yes, though often a much smaller one. The trigger is grease-producing fixtures, not the sign on the door.

A cafe pulling espresso and selling pastries baked offsite has very little in the way of fats, oils and grease going down a drain, and the requirement scales down accordingly. Start doing paninis, breakfast sandwiches, soups or anything on a flat top, and you are producing grease-laden waste like any other kitchen. This is the same logic that decides your ventilation, and we walk through that split in our Type 1 vs Type 2 hood guide for Ottawa cafes and restaurants. Menu drives equipment. Equipment drives code.

Do not size the interceptor to the menu you are opening with if you plan to expand it in year two. Rebuilding an undersized interceptor after the floor is poured is one of the more expensive corrections in a fit-out.

What size grease interceptor do you need?

Sizing comes from the fixtures that discharge grease, not from your seat count or your square footage. The Building Code points to the CSA B481 series of standards for the material, sizing, selection and installation of grease interceptors, and B481.3 is the one that covers sizing calculations based on peak flow.

In practice your mechanical designer or a licensed plumbing contractor totals up the grease-producing fixtures, works out peak flow and picks a certified unit from there. Two things that catch owners out.

Only grease-producing fixtures should run through the interceptor. Routing your mop sink, your washrooms or your floor drains into it dilutes the flow, shortens the effective retention time and gets flagged on inspection.

Dishwasher discharge is its own conversation. Hot water and detergent can push grease straight through an interceptor in liquid form so it re-solidifies in the City sewer downstream, which is the exact thing the by-law exists to prevent. How the dishwasher ties in has to be designed deliberately.

Where does the interceptor go, inside or outside?

It depends on the size, and the size depends on your kitchen. Small hydromechanical units sit indoors, close to the fixtures they serve, often under a sink or in the floor nearby. The Code wants the interceptor as close as possible to what it serves. Large gravity interceptors are concrete tanks that go in the ground outside.

That indoor or outdoor decision has real consequences for your budget and your schedule, so settle it early.

An indoor unit means floor coring, drain re-routing and losing usable kitchen floor area. In a tight downtown unit that floor space is not free.

An outdoor in-ground tank means excavation, a service vehicle that can reach it and landlord permission to dig. If you are leasing a unit in a plaza, the right to excavate the parking area is not something you assume. It goes in the lease. This is exactly the kind of clause we tell tenants to look for in our post on 5 things to check before signing a commercial lease in Ottawa.

Access for cleaning matters as much as the install. A tank you cannot reach with a pump truck is a tank that does not get serviced properly.

Do you need a permit to install a grease interceptor in Ottawa?

Yes. Interceptor work is plumbing work, and plumbing goes through the City's Building Code Services, not Ottawa Public Health. Which fee applies depends on whether the interceptor is a standalone change or part of a larger fit-up.

The permit fees come from the City's Building Code Services Fee Schedule. The install range is our own Ottawa field range, not a published City number, and it moves a lot with size, whether you are excavating and how much drain re-routing the existing slab forces on you.

Almost nobody permits an interceptor on its own. It rides along with the rest of the fit-up, which is how the fee usually lands in the second row rather than the first. For the wider permit picture, our post on what permits you need for a commercial fit-up in Ottawa lays out the full set.

Ottawa Public Health is a separate review running in parallel, and it does care about the drainage layout. Plans to establish, build, change or significantly renovate a food premises need approval from a Public Health Inspector, and OPH asks for three copies of your building and equipment plan showing every room and every piece of equipment. Their page is also explicit that a Public Health approval does not mean zoning, building or any other authority has signed off. Two reviews. Two desks. Both have to clear.

How often does a grease interceptor have to be cleaned?

On a set schedule, and the Sewer Use By-law sets the threshold rather than leaving it to judgment. Service is due before the accumulated solids and grease build up far enough to stop the unit working as designed, and the by-law also requires you to keep the maintenance records to prove it. A compliance officer can enter and inspect the interceptor and ask for those records.

Confirm your exact servicing interval and the record retention period for your unit directly with the City's Sewer Use Program at 613-580-2424 extension 23326 or [email protected], because the threshold in the by-law is specific and the answer depends on your interceptor's volume.

Three habits keep kitchens out of trouble, and all three come straight from the City's own guidance. Use sink basket strainers on every drain. Scrape and wipe grease into the green bin or garbage before anything gets washed. Never use degreasers, emulsifiers or hot water to chase grease down a drain, because all you are doing is moving the problem into the City sewer where it costs more to fix.

What happens if you skip it or neglect it?

The by-law carries penalties and fines. That is the part owners expect. The part they do not expect is worse.

If a sewer blockage happens, a public health inspector can close the restaurant until the repairs are done. That is the City's own stated consequence, and it is a closure with no notice, in the middle of service, with staff scheduled and product in the walk-in. A neglected interceptor is not a maintenance line item. It is a business continuity risk.

There is a quieter cost too. Grease build-up in the sewer system raises City operating costs, which feeds back into sewer rates for every Ottawa business including yours.

When should you deal with this in your fit-out schedule?

Early, during design, before anyone touches the slab. Interceptor location is a slab and drainage decision, and slab work is the least reversible part of a restaurant fit-out.

Restaurant construction in Ottawa typically runs 10 to 16 weeks, and an interceptor that gets designed properly at the front end is a normal line in that schedule. One discovered late is a change order, a re-core, a re-inspection and lost weeks. We see this most often in second-generation spaces where an owner assumes the previous tenant's interceptor is fine. Sometimes it is. Often it is undersized for the new menu, or it was never maintained and needs replacing. Check it before you sign, because a second-generation space can otherwise save you 30 to 50 percent against a cold shell and that is worth protecting.

For how the whole sequence fits together, see our cafe and restaurant fit-out owner's guide for Ottawa, the numbers in how much a restaurant fit-up costs in Ottawa and the full Commercial Fit-Out in Ottawa complete 2026 guide.

FAQ

1. Do I need a grease trap for my restaurant in Ottawa?

Yes. The Ontario Building Code requires a properly sized grease interceptor anywhere food is cooked, processed or prepared, and the City of Ottawa Sewer Use By-law 2025-94 limits grease discharge to the sewer and is enforceable with penalties and fines.

2. What size grease interceptor do I need?

It is calculated from the peak flow of the fixtures that actually produce grease, using the CSA B481 series referenced by the Building Code. Your mechanical designer or a licensed plumbing contractor runs that calculation. Seat count and square footage do not determine it.

3. Do I need a permit to install a grease interceptor in Ottawa?

Yes. It is plumbing work permitted through the City's Building Code Services. Plumbing-only work is $117 per application as of January 1, 2026. If the interceptor is part of a larger fit-up it falls under the fit-up permit at $12.75 per $1,000 of assessed value of work, minimum $117.

4. Does a coffee shop need a grease interceptor?

Usually yes, though often a small one, and the requirement is driven by grease-producing fixtures rather than by the type of business. An espresso and pastry cafe generates very little. Add a flat top or a fryer and you are in the same territory as a full kitchen.

5. How much does a grease interceptor cost in Ottawa?

Supplied and installed, roughly $5,000 to $25,000 in our experience on Ottawa projects. The spread comes down to size, whether it goes indoors or in the ground outside and how much existing drainage has to be re-routed.

6. Can I reuse the grease interceptor from the previous tenant?

Sometimes, but verify it before you commit. It has to be correctly sized for your menu and equipment, not the last operator's, and it has to have been maintained. Have it inspected during your due diligence rather than after you sign the lease.

Planning a restaurant or cafe fit-out in Ottawa?

Noblestar Construction is a commercial fit-out general contractor in Ottawa. We build restaurant, cafe, retail, wellness, healthcare and office spaces, and we coordinate the City permit reviews, Ottawa Public Health and the licensed trades alongside the build so problems like this get solved on paper instead of in the slab. Call 613-790-6128 or book a fit-out consultation.