Innisfil Basement Apartment and Garden Suite Rules: 2026 Guide
If you own a house in Innisfil, the Town lets you add up to two extra units on most residential lots: a basement apartment, a unit over the garage, or a garden suite in the backyard. The Town's public register shows 25 new accessory units registered in 2026 as of October 20, so plenty of homeowners are already doing it. Here are the Innisfil basement apartment and garden suite rules in plain English, plus what to check if you're buying a house that already has one.
I'm Darren Cabral, REALTOR® with Cabral Real Estate at CV Real Estate, Brokerage. Buyers ask me about income suites every week, and sellers ask whether their suite adds value. The answer almost always starts with one question: is it registered with the Town? Let's walk through how that works.
The short version
How many units: up to two accessory dwelling units on an eligible single-detached, semi-detached or street townhouse lot, according to the Town of Innisfil.
Where you can't: the Cookstown settlement area, lots with a private septic system within 100 metres of Lake Simcoe, and hazard lands like flood-prone areas.
How big: no more than 50% of the main house's gross floor area, up to 100 square metres, with up to 3 bedrooms per unit.
Costs: a building permit, but no development charges and no registration fee, per the Town's homeowner's guide.
Funding: the County of Simcoe offers a forgivable loan of up to $50,000, with 15 years of rent limits attached.
Buying one: check the Town's public register of legal units before you count on the rent.
What counts as an accessory dwelling unit in Innisfil?
The Town calls them accessory dwelling units, or ADUs. You'll also hear secondary suite, in-law suite, basement apartment, granny flat, garage suite, coach house and garden suite. They all mean the same thing: a self-contained unit with its own kitchen, bathroom and sleeping space on the same lot as an existing house.
You can live in it, have family live in it, or rent it out. What you can't do is sever it and sell it separately. The unit stays part of the property.
Where you can and can't add one
Innisfil's rules come from By-law 043-21, which amended the Town's comprehensive zoning by-law to allow up to two accessory units. Before you spend money on drawings, run through the Town's basic screening:
House type: you need a single-detached, semi-detached or street townhouse.
Not in Cookstown: the Town's guide says units can't be built in the Cookstown settlement area at this time because of wastewater servicing constraints.
Not on a private septic near the lake: lots with a private septic system within 100 metres of the Lake Simcoe shoreline are excluded.
Not on hazard lands: flood-prone or erosion-prone properties are out, as determined by the conservation authority.
Conservation authority permit: if your lot is in the regulated area of the Lake Simcoe Region or Nottawasaga Valley Conservation Authority, you need their permit before the Town will issue a building permit.
Shoreline properties: lots in the Our Shore area fall under the Town's Community Planning Permit System instead of the regular zoning by-law, so check that document.
On a private well and septic lot elsewhere in town, you can still add a unit, but you have to show the systems have enough capacity for it.
Size, bedrooms, entrance and parking
Here are the main zoning standards from the by-law and the Town's guide:
Size: each unit can be no more than 50% of the main house's gross floor area, up to 100 square metres (about 1,076 square feet). Garages, unfinished basements and mechanical rooms don't count toward the house's floor area.
Bedrooms: up to 3 per unit.
Entrance: every unit needs its own separate entrance, reached by a path at least 1 metre wide.
Parking: the Town's guide calls for 2 off-street spaces on a lot with 1 unit and 4 with 2 units. Tandem parking counts, and garage spaces count. Each space must be at least 2.5 metres by 5 metres, and at least 40% of the front yard has to stay landscaped.
The Town's own example: a bungalow with a 90 square metre main floor and a finished basement of 80 square metres (after the service room) has 170 square metres of floor area, so the unit can be up to 85 square metres.
Garden suites and other detached units
If you'd rather build in the backyard or over a detached garage, the extra rules are:
Height: no taller than the main house or 6 metres, whichever is less.
Distance: within 60 metres of the house, and not in the front yard.
How many: two detached units only on lots of at least 1,000 square metres. Smaller lots get one, with no balcony.
Footprint: up to 50 square metres each, a combined maximum of 50% of the rear yard, and at least 25% of the rear yard kept as landscaped open space.
Setbacks: at least 1.2 metres from the rear and side lot lines, and 3 metres from an exterior side lot line on a corner lot.
Prefab units: the Town treats a factory-built or mobile unit the same as any other. It still needs a proper foundation and servicing under the Building Code.
Permits, fees and registration
Every unit needs a building permit, or a change of use permit to legalize one that's already built. Electrical work needs a separate permit from the Electrical Safety Authority. The Town's guide says a complete application gets a permit or a request for more information within 15 business days.
Development charges: none for creating an accessory dwelling unit, per the Town's guide.
Permit fees: the 2023 guide listed $1.88 per square foot for additions and new construction, $0.60 per square foot for interior renovations, and $129.90 for the zoning permit. Fees are reviewed every year, so check the Town's current Fees and Charges By-law.
Registration: automatic once your permit passes the Notice of Completion inspection. No application, no fee and no renewal.
Address: the unit gets its own "Unit 2" or "Unit 3" address for emergency services, mail and garbage pickup.
Fines: an unregistered or non-compliant unit can be hit with fees starting at $350 and fines of up to $100,000 on conviction.
My advice: hire a qualified designer. The Building Code rules for ceiling heights, fire separation, egress windows and smoke alarms are detailed, and a clean first submission saves weeks.
The County's $50,000 forgivable loan
The County of Simcoe's Secondary Suites Program offers a 15-year forgivable loan of up to $50,000 to create a secondary or garden suite. No payments and no interest as long as you follow the agreement, and the balance is forgiven in equal amounts each year. The catch is real, so read the program FAQ before you apply:
Rent must stay at or below CMHC average market rent for 15 years, with heat, hydro, water and hot water included.
Your tenant has to meet provincial income limits, and the unit has to be rented within two months of completion.
The loan is registered as a mortgage on title. If you sell before year 15, the unforgiven balance is due.
You must apply before construction starts. Funding is limited and first come, first served.
For a family suite or a long-term hold, the loan can make a lot of sense. If you plan to sell in a few years or want market rent, run the numbers both ways.
Buying a house with a basement apartment in Innisfil
This is where I see buyers get burned. A listing that says "in-law suite" or "income potential" doesn't tell you whether the unit is legal. Here's my checklist:
Check the register. The Town lists every registered unit by address on its accessory dwelling units page. If the address isn't there, treat the suite as unregistered.
Ask for the paperwork. Building permit, final inspection and ESA certificate. Make your offer conditional on reviewing them if they aren't in the listing package.
Talk to your lender early. Whether a lender will count rental income from the suite can depend on whether it's legal. Get that answer before you firm up.
Know the tenant situation. If someone lives there, the Residential Tenancies Act applies and the tenancy carries over to you. Get the lease and rent details in writing.
Don't plan on Airbnb. Innisfil's short-term accommodation rules only allow short-term rentals as a bed and breakfast where the owner lives in the home, with up to 3 guest rooms and no kitchens in the guest rooms.
For context, Innisfil's average sold price was $747,652 in September 2026 across 56 sales, with a median of $707,500, according to WOWA's Innisfil market report. A legal suite can help a buyer carry a home at that price, but only if the rent is real and the unit is registered.
New to buying here? My Innisfil buyer's guide covers the neighbourhoods, and my free buyer's guide walks through offers, closing costs and due diligence.
Selling a home with a suite
If your unit is registered, say so in the listing and have the permit and inspection documents ready. Buyers and their lenders will ask. If it isn't registered, talk to me before you list. Sometimes legalizing it first is worth it, and sometimes it's better to price and market the space as part of the main house. My AI home valuation gives you a starting number, and my five seller tips cover the basics of getting ready.
A note for investors
Innisfil's rules make a house plus one or two legal units a realistic small-investor play, as long as you underwrite the real costs: design, permits, construction, parking and the time it takes. My investor guide covers how I run the numbers on Simcoe County deals, and my off-market deals list is where I share opportunities before they hit the open market.
FAQ
Can I put a basement apartment in my Innisfil house?
Probably, if you own a single-detached, semi-detached or street townhouse. The Town allows up to two accessory dwelling units on eligible lots. They are not permitted in the Cookstown settlement area, on lots with a private septic system within 100 metres of Lake Simcoe, or on hazard lands. You need a building permit, and the unit has to meet the zoning by-law and the Ontario Building, Fire and Electrical Codes.
How big can a basement apartment or garden suite be in Innisfil?
Under the Town's zoning rules, an accessory unit can't be more than 50% of the gross floor area of the main house, up to 100 square metres (about 1,076 square feet), with a maximum of 3 bedrooms. A detached unit has a 50 square metre footprint limit, can't be taller than the house or 6 metres, and must be within 60 metres of the house.
Do I pay development charges to add a unit in Innisfil?
The Town's homeowner guide says there are no development charges for creating an accessory dwelling unit, and no registration or renewal fee. You still pay building permit fees, which the Town reviews every year.
How do I know if a basement apartment in Innisfil is legal?
The Town publishes a list of registered accessory dwelling units on its website. A unit is registered automatically once its building permit passes the final Notice of Completion inspection. If the address isn't on the list, treat the unit as unregistered until the seller proves otherwise.
Is there funding to build a secondary suite in Innisfil?
The County of Simcoe's Secondary Suites Program offers a 15-year forgivable loan of up to $50,000 to create a secondary or garden suite. In exchange, the rent has to stay at or below CMHC average market rent for 15 years, utilities included, and the tenant has to meet income limits. You must apply before construction starts, and funding is first come, first served.
Next steps
Looking at Innisfil? Start here:
Innisfil Real Estate Guide: Alcona, Lefroy, Stroud, Cookstown and the lakeshore, plus buying and selling tips
Listing Alerts: new Innisfil listings that match your search, sent straight to you
Off-Market Deals: investment opportunities before they're public
AI Home Valuation: a quick estimate of what your home could sell for
Investor Guide: how I look at rental and multi-unit deals in Simcoe County
Or call or text me at 647-371-5335, or email darren@cabralrealestate.ca. CV Real Estate, Brokerage office: 705-704-1188.
This post is general information, not legal, tax, financing or construction advice. Zoning standards are from the Town of Innisfil's Accessory Dwelling Units webpage, By-law 043-21 and its Accessory Dwelling Units Homeowner's Guide (April 2023). Provincial rules for additional units have changed since some of these documents were published, and fees are reviewed every year, so confirm current standards for your property with the Town of Innisfil (705-436-3710) before you design, buy or build. Funding details are from the County of Simcoe's 2025 to 2026 Secondary Suites Program fact sheet and FAQ and can change. Market figures are from WOWA for September 2026. The registration count is from the Town's public register as of October 2026.
Comments