Do You Need a Permit for a Kitchen or Bathroom Renovation in St. Thomas or London?
Short answer: new cabinets and paint, no. Moving a sink, a toilet, a wall or a window, yes. New wiring, an ESA notification almost every time. Here is where the lines sit in St. Thomas and London, taken from the cities' own pages, and what to ask whoever does the work.
Most homeowners we meet at the kitchen table ask the permit question one of two ways. Either "Do we really need one for this?" or "Can we skip it to save time?" Both are fair questions. The honest answer depends on three things: what you are changing, which municipality you live in, and whether any wiring is involved. Paint and cabinets almost never need a permit. Moving plumbing, walls or windows almost always does. And electrical work runs on its own separate system that most people have never heard of.
Below is what the City of St. Thomas and the City of London say on their own websites, read on 4 October 2026, plus the provincial electrical rules that apply everywhere in Ontario.
Why permits exist (and whose job it is)
Ontario's Building Code is provincial, but enforcing it is the job of municipal building officials, as the Province's Building Code page puts it. In practice that means your city reviews the drawings before work starts, then sends an inspector to look at things like framing, plumbing and insulation before the walls are closed.
One line on the City of St. Thomas building permits page is worth reading twice: it is the responsibility of the property owner, or their authorized agent, to get the permit before work begins. A contractor can apply on your behalf (we handle permit applications on projects that need them), but if nobody does, it is your house, and your name the city will be looking for.
St. Thomas: what the City says
St. Thomas lists the work that generally needs a building permit: new buildings, additions, renovations or alterations, structures over 10 square metres (108 sq. ft.), and plumbing work, fixtures and service systems.
The City's plumbing permits page is broader than many homeowners expect. It says a plumbing permit is generally required for new plumbing, repairs, replacements or renewals of plumbing components, and alterations. In other words, do not assume a like-for-like swap is exempt in St. Thomas. Call Planning & Building Services and ask about your exact job before you book the plumber.
On timing, the St. Thomas permit process page says plan review takes 10, 15, 20 or 30 business days depending on the size of the project, and that construction may only begin once the permit has been issued. The fee is worked out during plan review and set in the City's Building By-law. Some properties also need other sign-offs first, such as heritage approval or a conservation authority (Kettle Creek or Catfish Creek). Once you have a permit, inspections are booked on 519-631-9587 or inspection@stthomas.ca with at least 48 hours' notice.
London: the City's do and don't lists
London publishes the clearest list we have seen, on its before you apply for a building permit page. For kitchens and bathrooms, these are the lines that matter:
| Kitchen or bathroom job | London permit? |
|---|---|
| New cabinets or cupboards | No |
| Painting | No |
| Replacing a sink, tub, toilet or shower in the same spot | No |
| Adding, removing or relocating a sink, tub, toilet or shower | Yes |
| Plumbing drainage: installing, replacing or repairing | Yes |
| Interior alterations (moving or removing walls) | Yes |
| Adding a window or door, or making one bigger | Yes |
| Replacing a window or door with the same size | No |
| Alterations to furnace ducts | Yes |
| Finishing a basement into rooms or living space | Yes |
London also says complete small-scale residential applications are reviewed within 10 business days, and it offers a meeting with a Plan Examiner before you apply. If your house is in a heritage district, a separate heritage alteration permit may apply too.
Electrical is a separate permit, everywhere in Ontario
This is the one people miss. A building permit does not cover the wiring. Electrical work is reported to the Electrical Safety Authority (ESA) through a "notification of work", which most people call an ESA permit. The ESA's homeowner page says the Ontario Electrical Safety Code requires almost all electrical work to be reported this way, before the work starts, and that you may need both a building permit and an ESA notification.
A typical kitchen renovation adds circuits for the counters, the range or the dishwasher, and new lighting. A bathroom adds a fan, lighting, maybe a heated floor. All of that is electrical work.
Who can do it matters as much as the paperwork. According to the ESA, a Licensed Electrical Contractor (LEC) is the only business you can legally hire to do electrical work in your home, and a general contractor is not licensed to do it themselves. An LEC has a 7-digit ECRA/ESA licence number, which should appear on their estimate. When the work passes, ESA issues a Certificate of Acceptance; ask for a copy, because your insurer or a future buyer may want it. ESA also lists it as a red flag if a contractor asks you to file the notification in your own name.
A quick way to sort your own project
Go room by room and put each item of your plan into one of three columns:
- Finishes only: paint, cabinets, countertops, backsplash, flooring, swapping a faucet. Usually no building permit. In St. Thomas, check any plumbing replacement with the City first.
- Moving or adding things: a sink to an island, a toilet across the room, a tub turned into a walk-in shower with a new drain, a wall taken out, a new window. Plan on a building and/or plumbing permit, and drawings.
- Anything with wires: new outlets, circuits, pot lights, a range hood, an exhaust fan, in-floor heat. Plan on an ESA notification filed by a Licensed Electrical Contractor.
If anything lands in the second or third column, the permit belongs in your timeline as well as your budget. For a St. Thomas job, plan review alone can run 10 to 30 business days, which is two to six weeks before anyone is allowed to start that part of the work. Build that into the date you tell the family the kitchen will be out of action.
What happens if you skip it
The city can order work stopped, and an inspector cannot check a drain or a wire that is already behind new drywall, so opening it back up is a real risk. The ESA notes that insurance claims linked to unlicensed electrical work may be denied. And when you sell, a buyer's home inspector or lawyer may ask for permits and the ESA certificate for a renovated kitchen or bathroom. A permit is a few weeks and a fee now; a missing one can cost a lot more later.
Five questions to ask any contractor
- Which permits does this job need, and who is applying for them? Is that in the written quote?
- Is the permit fee included in your price, or extra?
- Who is doing the electrical, and what is their ECRA/ESA licence number?
- Will I get a copy of the permit, the passed inspections and the ESA Certificate of Acceptance at the end?
- Does your schedule allow for the City's plan review time, or does the start date assume the permit is already issued?
Good answers are specific and in writing. Our own quotes are fixed and itemized, and on projects that need a permit we handle the application. If you want to see where a project sits on cost before you get that far, our 2026 cost guide has the three local price ranges, and our post on how to compare renovation quotes has a checklist that includes permits.
Questions homeowners ask
Do I need a permit to replace kitchen cabinets in London or St. Thomas?
No building permit is needed for cabinets on their own. London lists cabinetry and cupboards as work that does not need a permit. If the job also moves a sink or adds wiring, those parts may need a plumbing permit or an ESA notification.
Do I need a permit to turn a tub into a walk-in shower?
Usually yes, if the drain or the fixture moves. London requires a permit for adding, removing or relocating a tub or shower and for drainage work. St. Thomas says plumbing alterations and replacements generally need a plumbing permit, so call 519-633-2560 to confirm.
Can my general contractor do the electrical work in my kitchen?
Only if they are also a Licensed Electrical Contractor. ESA says a general contractor is not licensed to do electrical work, so the wiring must be done by an LEC, who files the ESA notification and arranges inspection.
How long does a permit take in St. Thomas?
The City says plan review takes 10, 15, 20 or 30 business days depending on the size of the project, and work can only start once the permit is issued. Missing information adds time, so apply with complete drawings.