Legal Basement Apartment in Markham (2027): Rules, Permits and Costs

By Jatin Dua · Broker of Record, RE/MAX Quantum Realty · Updated 2 November 2026 · 10 min read — Markham’s zoning, Building Code and fire registration rules for a basement suite in 2027, with the City’s 2026 fees worked through on a sample unit.

This guide is for Markham homeowners planning a basement suite, families making room for a parent, and buyers looking at a house that already has a second unit. You will get Markham’s zoning and parking rules, the 2024 Building Code checks the City inspects, the fire department registration that Markham requires, and the 2026 fees, worked through on a sample suite.

Can you have a legal basement apartment in Markham in 2027?

Yes. Markham’s registration page says that, because of the province’s More Homes Built Faster Act (Bill 23), every urban residential lot can now have up to three units. A basement apartment is the most common way to add one of them. The City’s April 2026 homeowner guide says suites can go in detached houses, semi-detached houses and row townhouses.

Legal in Markham means three things, in this order:

1. The suite meets zoning.
2. It is built under a building permit and passes every inspection.
3. The finished two-unit house is registered with Markham Fire and Emergency Services.

Skip any one of these and the unit is not legal, no matter how well it is finished.

Two units in the house, three on the lot

The City’s guide notes that under the Ontario Building Code a house can contain only two dwelling units in total: the main home and the secondary suite. A third unit on the lot would be a separate structure, such as a coach house or garden home. My post on moving a parent in compares in-law suites with garden suites if you are weighing both.

What are Markham’s zoning rules for a basement suite?

Markham’s guide summarizes Zoning By-law 2024-19. Your property may still fall under an older by-law, so use the City’s free Property Details Search to confirm which one applies. The key rules in the guide:

• One door facing the street: only one unit entrance is allowed on any main wall facing a street, unless the second entrance is below grade.
• Side entrances: a suite entrance from the side yard must be at least 1.2 metres from the side lot line, and stairs to the suite cannot sit within 1.2 metres of that line.
• Parking: a house with a secondary suite needs one space for the main home and one for the suite. Each space must be at least 2.75 by 5.8 metres.
• No street parking: public streets and lanes do not count as parking for the suite.
• Garden home or coach house: one more space for that unit.

Other setbacks depend on your zone. If your lot cannot meet a rule, the route is a minor variance, which adds time and cost.

What Building Code rules does Markham inspect?

Which rules apply depends on the age of your house. A house less than five years old must meet Part 9 of the 2024 Ontario Building Code. An older house can use Part 11, which offers more flexible options. Most Markham basements are in houses older than five years.

Source: City of Markham, Secondary Suites Guide for Homeowners, April 2026, based on the 2024 Ontario Building Code. Summary only; your designer must check the full Code.

The checks that sink most basements

• Ceiling height: 1.95 metres in the suite, 1.85 metres under beams and ducts, and 2.10 metres in shared areas.
• Bedroom windows: at least 0.35 m² of clear opening, no side under 380 mm, openable without tools. A window in a window well needs 550 mm of clear space in front of it.
• Exits: you must not have to travel more than one storey to get out, and the exit path cannot pass through the other unit or a service room.
• Fire department access: generally a clear 1.2-metre path from the street to the suite door, and no more than 45 metres from the fire truck to the entrance.
• Plumbing: each unit needs a kitchen sink, a basin, a tub or shower and a toilet, plus its own water shut-off valve. Laundry can be shared. Flood-prone lots need a backwater valve for each unit.

How do you get a building permit for a second suite in Markham?

Markham takes permit applications online through its ePLAN portal. Every application has four parts: forms, documents, construction drawings and the permit fee. The guide says drawings can be prepared by a designer with a BCIN (Building Code Identification Number) qualified in House or Small Buildings, a licensed architect, a professional engineer, or the homeowner, if they understand and accept responsibility for the Code.

Ontario’s guide to adding a second unit says you should hear within 10 business days whether a complete application is approved. Incomplete or poorly designed applications take longer.

Which inspections will you need?

Book each at least 24 hours ahead through ePLAN. The guide lists:

• footings and foundation, if you add a walkout or new foundation;
• framing, before insulation or drywall;
• plumbing and mechanical rough-in;
• insulation and vapour barrier;
• fire separations and fire stopping, where they apply;
• occupancy or completion, when the unit is finished.

If an inspector finds a problem, you get a Field Inspection Report and must fix it and be re-inspected before moving on. Electrical work is inspected separately under the Ontario Electrical Safety Code.

Do you have to register a basement apartment in Markham?

Yes. Markham’s Two-Unit Residential Occupancies By-law (2018-57) requires every two-unit house to be registered. After the permit is closed, Markham Fire and Emergency Services inspects both units and the rest of the house. For registration you must provide or pass:

• proof of home insurance that covers two units;
• a general electrical inspection report;
• working smoke and carbon monoxide alarms on every level, in date and correctly powered;
• a check that the stove and dryer exhaust ducts use semi-rigid or smooth metal;
• a self-closing, latching door between any attached garage and the house.

Once everything passes, the fire department issues a letter confirming registration. The City warns that occupying an unregistered two-unit house can lead to court action and fines.

What about a suite that is decades old?

Markham’s page says a suite that predates a cut-off date in the early 1990s may be assessed under the Fire Code’s retrofit rules for two-unit houses (Section 9.8) instead of the current Building Code, using a Two-Unit House Declaration Form. The page names July 1, 1993, while the Fire Code itself defines an existing suite as one in place on July 14, 1994. Ask Markham Fire which date it applies before you rely on it, and gather proof of age such as old leases, tax records or permits.

How much does a legal basement suite cost in Markham?

Markham publishes its fees, so here is a worked example for a 75 m² basement suite in an older house, with one new below-grade stair, two enlarged bedroom windows and five new plumbing fixtures. These are City fees only, not construction.

Source: City of Markham Building By-law 2025-121, Schedule A (fees for applications submitted after December 31, 2025); City of Markham registration page for basement apartments and second suites. Example is illustrative; your permit examiner confirms the final fee.

Other costs to plan for:

• Development charges: Ontario’s guide says they are not collected for a second unit built in an existing house.
• Backwater valve: $151 each in Markham’s plumbing fees, where one is needed.
• Construction: I could not find an official, reliable cost per suite for Markham. Ceiling height, a walkout or new stair, fire-rated drywall and electrical upgrades drive most of it. Get at least three written quotes.
• Financing: CMHC’s insured refinance for adding units allows up to 90% of the as-improved value, a value under $2,000,000, up to four units and up to 30 years, for owner-occupied homes. The suite cannot be a short-term rental.

What is a Markham house worth as a starting point?

MLS data does not flag which homes have registered suites, so there is no verified “suite premium” for Markham. Here is the base for the three home types that can hold a basement unit.

Source: TRREB MLS data via REALM, January–October 2026 vs the same period of 2025, City of Markham as a whole. Median prices; not specific to homes with suites.

For the factors that move a single home’s price, see my guide to what a Markham house is worth, and for the year ahead, the Markham and Richmond Hill market outlook for 2027.

What should landlords in Markham sort out before renting?

• Insurance: registration needs proof of coverage for two units. My guide to landlord insurance in Ontario explains the gaps to check.
• Rent rules: Ontario says most new basement apartments first occupied as homes after November 15, 2018 are exempt from the rent increase guideline, which is 1.9% for 2027. Older units are not.
• Lease: most Ontario tenancies use the province’s standard lease.
• Tax: rental income must be reported, and some expenses can be deducted.

What to do next

1. Run your address through Markham’s Property Details Search to confirm your zoning by-law.
2. Measure ceiling heights, bedroom windows and the side yard where the entrance would go.
3. Hire a qualified designer and apply through ePLAN with complete drawings.
4. Book every inspection, close the permit, then book the fire registration inspection.
5. If you are buying or selling, ask for the permit and registration letter in writing.

Frequently asked questions

Sources

• City of Markham: Secondary Suites Guide for Homeowners (April 2026)
• City of Markham: Registration, Basement Apartments and Second Suites
• City of Markham: Building permit fee schedule (2026, By-law 2025-121)
• Government of Ontario: Add a second unit in your house
• Ontario Fire Code, O. Reg. 213/07, Section 9.8 Two Unit Residential Occupancies
• Residential Tenancies Act, 2006 (e-Laws)
• CMHC Refinance fact sheet (secondary suites)
• Government of Ontario: Residential rent increases

Related reading

• How Much Does a Fourplex Cost to Build or Buy in Toronto?
• Converting a House to a Triplex in Toronto: Cost, Permits and Payback
• Multiplex Benefits for Toronto Homeowners: Rent, Value and Family Living
• Legal Basement Apartment in Brampton (2027): Rules, Permits and Costs