Ask an operator what they expect to worry about and they will say equipment, or rent, or staffing. Nobody says grease interceptor. Then they buy a second-generation space with an undersized one buried under a slab, and it becomes the most expensive plumbing decision of the project.
What it does and why it exists
Fats, oils and grease congeal in sewers. Municipalities are consistent about not wanting that, so any premises putting grease into the drain is required to intercept it before it leaves the building. The device separates grease and solids from the wastewater, holds them, and gets pumped out on a schedule.
It is not optional, it is inspected, and it is tied to your approvals. Which means it sits on the chain that leads to occupancy.
Where projects get caught
Sizing is calculated, not guessed. The size depends on your fixtures, your flow rates and your menu. An interceptor sized for the previous tenant’s café is frequently not sized for your kitchen. This is a calculation your designer does and the authority reviews — and it is a calculation that has to be in the permit package. Its absence is a common cause of a comment letter, which costs a full review cycle.
Location decides the cost. An interceptor needs to be accessible for servicing. Under a slab in the middle of a dining room is legal and awful. Outside in a parking area is convenient but may need the landlord’s consent and a municipal approval. Somewhere in back-of-house is usually best and consumes floor area you were planning to use for something else.
Retrofitting means opening the floor. If the existing unit is the wrong size or in the wrong place, replacing it means breaking concrete, re-running drainage, and restoring the slab. That is a serious line item in a project that was budgeted as a cosmetic refresh, and it comes with schedule.
The menu can change the answer. Adding a fryer to a concept that was going to be sandwiches changes your grease load and can change the interceptor requirement, along with the hood. This is another reason the menu belongs at the start of design rather than the middle of construction.
The second-generation trap
Second-generation spaces are usually the right choice. They come with services already in place and they save real money. But the existing interceptor is one of the specific things worth verifying rather than assuming, because “there is already one” is not the same as “there is a suitable one.”
What to establish before you sign:
- Is there one, and where exactly? Get it located, not described.
- What size is it, and what was it sized for? The previous tenant’s menu may have been much lighter than yours.
- When was it last serviced, and is there a record? A neglected interceptor may be a maintenance problem you inherit.
- Is it accessible? A pumper truck needs to reach it.
- Who owns it under the lease? Shared interceptors serving multiple units exist, and they create shared obligations.
That last point is where arguments start. In a plaza with several food tenants on one interceptor, servicing cost and capacity are shared, and the allocation is whatever the leases say — which is sometimes nothing useful.
Get it into the lease
Before signing, establish in writing:
- Whether an interceptor exists and whether it is sized for your intended use
- Who pays if it must be upsized or relocated for your use
- Who is responsible for routine servicing, and how the cost is shared if it is shared
- What condition it must be left in at the end of the term
The middle two are the ones that cost money later. A landlord who says “there is a grease trap” during a viewing has told you nothing enforceable.
The maintenance nobody plans for
An interceptor is a service contract, on a schedule, for the life of the business. Skip it and you get backups, odour, a failed inspection, and potentially a by-law problem. Municipalities can and do require records.
Budget it as a recurring operating cost from day one, the same way you budget hood cleaning. Both are the sort of thing that gets deferred in a tight month and then costs considerably more than the deferral saved.
The practical takeaway
This is a small device that punches above its weight, and it is worth ten minutes of attention at the point where attention is cheap — before you sign.
When we review a space, the interceptor is on the checklist alongside gas service and roof access, and for the same reason: it is one of a small number of things that can turn an affordable second-generation unit into a slab-breaking project. Better to find out during a walkthrough than during plan review.
