You built a basement apartment. You pulled the building permit. You passed the final inspection. Now you think you are done.
You might not be.
The City of London has a second-unit registration requirement that catches many landlords off guard. It applies to basement apartments, above-garage suites, and other accessory dwelling units (ADUs) throughout the city. It is separate from the building permit process. It is also separate from the Rental Housing Licensing program.
Miss it, and you may be operating an unregistered unit — which creates problems with your rental unit licence, your insurance, and the city's property standards enforcement.
This guide explains what the registration program is, who needs to register, and exactly how to do it.
What Is the City of London Second Unit Registration Program?
The City of London's second unit registration program is a municipal process that formally records the existence of a second residential unit on a property.
Under London's Zoning By-law (ZBL-1) and its Official Plan, most residential properties in London are now permitted to have one second dwelling unit — a basement apartment, a garage conversion, a coach house, or an above-garage suite. This is the result of provincial legislation (Bill 23, the More Homes Built Faster Act) that required Ontario municipalities to allow second units as of right in most residential zones.
But "permitted as of right" does not mean "automatically legal to rent." The city still needs to know the unit exists, confirm it meets minimum standards, and assign it a proper municipal address before you can legally rent it as a dwelling.
That is what registration does.
Registration is how the city:
- Creates an official address for the second unit (e.g., "45 Main Street, Unit B")
- Confirms the unit meets minimum Ontario Building Code and fire safety standards
- Links the unit to the Rental Housing Licensing system so you can get (or keep) your rental unit licence
Who Needs to Register a Second Unit in London?
You need to register if you have a self-contained residential unit inside or attached to your primary dwelling that you rent — or plan to rent — to a tenant.
This includes:
- Basement apartments — a finished basement with its own kitchen, bathroom, and separate entrance
- Above-garage suites — a living unit built above a detached or attached garage
- Garden suites / coach houses — a separate small dwelling on the same lot as the primary home
- Side-door suites — a portion of a house converted into a separate dwelling with its own entrance
If your second unit was built before the current registration requirement existed — and many were — you still need to register it. The age of the unit does not exempt it. If you are renting it out, it needs to be registered.
Second Unit Registration vs. Building Permit vs. Rental Unit Licence
These are three separate requirements. Many landlords confuse them or assume one covers the others.
| Step | What It Is | Who Issues It |
|---|---|---|
| Building Permit | Approval to build or convert a space into a unit | City of London Building Division |
| Second Unit Registration | Official city record that the unit exists and meets standards | City of London Planning & Development |
| Rental Unit Licence | Annual licence to rent a residential dwelling | City of London Municipal Compliance |
You need all three for a new second unit. If your unit was built with permits years ago, you may already have the first covered — but you still need the second and third.
The rental unit licence cannot be issued for a second unit until that unit is registered. Registration comes first.
Step-by-Step: How to Register a Second Unit in London
Step 1: Confirm Your Zoning
Before anything else, confirm that your property is in a zone that permits a second unit. Most R1 through R6 zones in London now allow one second unit as of right under ZBL-1.
You can check your zone using the City of London's interactive mapping tool on london.ca. If you are not in a permitted zone, you would need a zoning amendment before proceeding — a more involved process.
Step 2: Ensure the Unit Meets Building Code Standards
A second unit registration triggers an inspection. Before you apply, the unit should meet the following Ontario Building Code and fire code requirements:
Ceiling height:
- Minimum 1.95 metres (about 6'5") in all habitable rooms
- Bathrooms and hallways can be slightly lower
Egress windows:
- Every sleeping room must have a window large enough to escape through in an emergency
- Minimum opening: 0.35 square metres, with no dimension less than 380mm
Fire separation:
- The second unit must be separated from the primary dwelling by a fire-rated assembly (typically drywall on both sides of the separation wall)
- The separation must provide minimum 30-minute fire resistance
Smoke and CO alarms:
- Interconnected smoke alarms in every bedroom, hallway outside each sleeping area, and on every storey
- Carbon monoxide alarms on each storey
Separate entrance:
- The second unit must have its own exterior entrance that does not pass through the primary dwelling
Plumbing:
- Kitchen and bathroom with functioning plumbing
- Hot and cold water supply
If your unit was built with permits and passed its final building inspection, it likely meets these standards. If it was built without permits — a common situation in London — you may need a retroactive permit and inspection before registration is possible.
Step 3: Apply for a Municipal Address
If the second unit does not already have its own address, you need to get one assigned before registration is complete. Contact the City of London Addressing Department (part of Development Services) to request a civic address for the unit.
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Address assignment is straightforward: the city assigns a unit identifier (Unit A/Unit B, or a suffix like "½" or "lower") and issues a formal address confirmation. This address is what goes on your tenant's lease, on utility accounts, and on the rental unit licence application.
Step 4: Submit the Second Unit Registration Application
The second unit registration application is filed through the City of London. Applications are submitted to the Planning and Development department or through the building permit portal, depending on whether the unit is newly constructed or existing.
Required documents typically include:
- Proof of property ownership (title or recent tax assessment)
- The municipal address assigned to the unit
- A basic floor plan or sketch showing the layout, room sizes, and location of fire separations, smoke alarms, egress windows, and entrances
- If applicable: copies of the building permit and final inspection records
Application fees vary and are set annually. Contact the city directly or check london.ca for the current fee schedule.
Step 5: City Inspection
After you apply, the city schedules an inspection of the second unit. The inspector confirms:
- The unit meets minimum building code and fire code standards
- Egress windows are present and correctly sized in all sleeping rooms
- Smoke and CO alarms are installed and interconnected
- Fire separation between the units meets minimum requirements
- The unit has a separate, working entrance
- Kitchen and bathroom are functional
This is not a building permit inspection — it is a zoning compliance and habitability check. If you have a building permit history for the unit, bring those records. They will speed things up.
If the inspector identifies deficiencies, they will issue a list. You fix the deficiencies and request a re-inspection.
Step 6: Registration Confirmed — Then Apply for Your Rental Unit Licence
Once the city is satisfied the unit meets standards, the second unit is registered. The city updates its records, the unit appears in the municipal address database, and you are cleared to apply for a Rental Housing Licence for the unit.
Operating a second unit as a rental before registration and licensing is complete puts you offside with the city. Fines under the Municipal Act can reach $25,000. More practically: it creates problems with your insurance, with the LTB if you ever need to file an application, and with any property standards complaints your tenant files.
How Long Does Registration Take?
Allow 4–8 weeks from application to confirmed registration, assuming no significant deficiencies are found.
Inspection scheduling is the main variable. The city's inspection queue fluctuates with demand. If your unit has obvious deficiencies that need repair, add time for the repair work and the re-inspection.
Plan ahead. If you intend to rent the unit, start the registration process before your prospective tenant's move-in date — not after.
What Happens If You Don't Register?
Several things can go wrong if you skip registration:
No rental unit licence. The city will not issue a Rental Housing Licence for a second unit that is not registered. If a bylaw officer investigates — triggered by a complaint, a property standards inspection, or a licence audit — you are operating without a licence. That is a bylaw violation with fines attached.
Insurance risk. Many homeowner and landlord insurance policies exclude rental income from unregistered, unpermitted units. A fire or liability claim in an unregistered unit can result in a denied claim. Review your policy carefully.
LTB complications. The LTB does not technically require a rental licence to hear your application — but if a tenant raises the unregistered status of the unit in a proceeding, it can affect remedies and complicate your position. Keep your paperwork clean.
Property standards enforcement. If the city opens a property standards file on your property and discovers an unregistered second unit, they will require registration before closing the file — and may issue orders in the meantime.
Frequently Asked Questions
Does every basement apartment in London need to be registered, even old ones? Yes. If you are renting it, it needs to be registered regardless of when it was built. The registration requirement is tied to current use, not construction date.
I have a building permit for my basement apartment. Is that the same as registration? No. The building permit covers the construction. Registration is a separate step through the Planning and Development department that creates the official city record of the unit and assigns it an address.
What if my basement apartment was built without permits? You will likely need a retroactive building permit before registration is possible. Contact the City of London Building Division to discuss the retroactive permit process. Some older units can be inspected and permitted after the fact; others require more substantial upgrades.
Can I have two second units on one property? Under the current ZBL-1, most residential properties in London are permitted one second unit. Properties in certain zones or on larger lots may be permitted additional units. Check your specific zone before assuming two units are allowed.
How much does second unit registration cost? City fees change annually. Check london.ca or contact the Planning and Development department for the current fee schedule. Budget for the application fee, any permit fees if you need a retroactive permit, and re-inspection fees if deficiencies are found.
Will registering my second unit trigger a property tax reassessment? Possibly. MPAC reassesses properties on a four-year cycle, and a registered second unit changes the classification of the property. This is not a reason to avoid registration — but it is worth knowing. Contact MPAC or a property tax consultant if this is a concern.
The Bottom Line
Registering a second unit in London involves three layers: the building permit (construction approval), the second unit registration (municipal record and address), and the rental unit licence (annual operating permit). All three need to be in place before you rent the unit legally.
The registration process is not complicated, but it takes time and requires an inspection. Start early. Get the address assigned. Have your unit in good condition before you apply.
If you are managing multiple London properties — or want to add a second unit and are unsure where to start — Prospera Properties handles the compliance legwork so you do not have to track three separate municipal processes across multiple files. Reach out to see how we work.
Social caption: London landlords — building a basement apartment is step one. Getting it registered is step two. Many landlords skip it and don't find out until there's a problem. Here's exactly how the City of London's second unit registration process works, what the city inspects, and what happens if you're not registered. Link in bio.