Mississauga is more generous with garden suites than its neighbours, and most homeowners do not know it.
In Oakville, a garden suite is capped at 13 ft 1 in — one storey, effectively. In Mississauga, if your lot is over 8,073 sq ft, you can build two storeys up to 22 ft 4 in. That single difference changes what the building can be: a one-bedroom flat becomes a two-bedroom suite with proper stairs and a real second floor.
Mississauga also asks for less. No additional parking space is required for a garden suite. The interior side setback on a single-storey suite is 2 ft, against 4 ft in Oakville. Building permit fees are refunded, and second and third units are exempt from most municipal charges.
Here is what the by-law actually permits, and what it means for your lot.
Mississauga garden suite rules (2026)
Detached additional residential units are governed by Table 4.1.1.14 of Zoning By-law 0225-2007, as amended. The standards split by whether you are building one storey or two.
| One storey | Two storey | |
|---|---|---|
| Permitted on | Any lot | Lots over 8,073 sq ft (750 m²) only |
| Max floor area, lot up to 5,920 sq ft | 592 sq ft (55 m²) | Not permitted |
| Max floor area, larger lots | 10% of lot area, to a cap | 10% of lot area, to a cap |
| Max height, sloped roof | 15 ft 1 in (4.6 m) | 22 ft 4 in (6.8 m) |
| Max height, flat roof | 9 ft 10 in (3.0 m) | 19 ft (5.8 m) |
| Interior side setback | 2 ft (0.6 m) | 5 ft 11 in (1.8 m) |
| Rear setback | 5 ft 11 in (1.8 m) | 5 ft 11 in (1.8 m) |
| Exterior side setback | 8 ft 2 in (2.5 m) | 14 ft 9 in (4.5 m) |
| Location | Rear yard | Rear yard, or exterior side yard on corner lots zoned R1, R2, R3, R8 |
Two limits apply on top of that table: the suite cannot be taller than your house, and it cannot cover more ground than your house.
Can you build two storeys? One number decides it
8,073 sq ft (750 m²). Above that, a two-storey suite is on the table. Below it, you are building one storey, whatever the rest of the numbers say.
It is worth measuring before you pay anyone to draw anything. A lot a few hundred square feet short of the threshold is a different project from one a few hundred over, and the difference is roughly a bedroom.
What Mississauga allows that Oakville does not
| Mississauga | Oakville | |
|---|---|---|
| Two-storey suite | Yes, on lots over 8,073 sq ft | No — 13 ft 1 in cap |
| Interior side setback | 2 ft (one storey) | 4 ft |
| Additional parking space | Not required | Required in some cases |
| Building permit fee | Refunded | Payable |
The City’s pre-approved plans
Mississauga publishes pre-approved studio and one-bedroom garden suite drawings, free to use. They shorten approval and cut design cost. You still need a site plan showing where the suite sits and a grading plan, and the pre-approved drawings only work if your lot suits the layout.
We will tell you honestly whether a pre-approved plan fits your lot, or whether you are better off with a custom design. Sometimes the free drawings are the right answer.
Fees, servicing and the things that catch people
- Permit fees are refunded for building or legalising an additional residential unit, and second and third units are exempt from most municipal charges.
- A new garden suite usually needs its own municipal address — $81.90 plus HST.
- Development charges still apply to garden suites.
- Water and sanitary either share the house’s connections or need separate ones through the Region of Peel.
- Fire access: an unobstructed hard-surfaced path 1.2 m wide and 2.1 m high, no more than 45 m from the street to the suite’s front door.
- Only one garden suite per lot, and no home occupation is permitted inside an additional residential unit.
- A lot with additional residential units may have one driveway only.
current as of July 2026.
What a Mississauga Garden Suite Costs
Most turnkey garden suites across the west GTA land between $250,000 and $450,000+ depending on size, site servicing runs, foundation conditions and finishes. We provide a fixed, itemized quote after a site and servicing review. For the full numbers walkthrough, read our guides: Garden Suites — Rules, Costs & Permits (2026) and Building a Garden Suite in Oakville, Burlington & Mississauga.
Why Build With Golden Brick Homes
- HCRA-licensed builder with Tarion-standard construction discipline on every suite
- One team for zoning review, drawings, permits, servicing and construction — one accountable contract
- Fixed, transparent scope and pricing, no surprise costs
- Broker + builder in one: we can tell you what a suite does to your property’s value and rental income before you spend a dollar
Start Your Mississauga Garden Suite
Every project starts with a feasibility conversation about your lot, servicing and budget. Schedule a free consultation or call +1 (647) 772-1642 — we also build custom homes across Mississauga.
Check what your Mississauga lot allows
Send us the address and we will tell you whether a one-storey or two-storey suite is possible, what size the by-law permits, and what it is likely to cost to build. No obligation.
Free garden suite check
Send me the address. I’ll tell you if the lot qualifies.
Whether a garden suite works comes down to the lot, not the design: rear yard size, setbacks, height limits, servicing capacity, access for construction and what the municipality allows on your specific property. Give me the address and I will tell you what is realistic there.
One business day. No cost, and I will tell you if the lot does not support one rather than sell you a drawing.
Rahul Kumar — HCRA-Licensed Custom Home Builder, Golden Brick Homes · Broker, Royal LePage Certified Realty. General information only; confirm current requirements with your municipality.
Frequently asked questions
Can I build a two-storey garden suite in Mississauga?
Only if your lot is larger than 8,073 sq ft (750 m²). On lots at or below that, a garden suite is limited to one storey. A two-storey suite can reach 22 ft 4 in (6.8 m) with a sloped roof, or 19 ft (5.8 m) with a flat roof, and it can never be taller than your house.
How big can a garden suite be in Mississauga?
On a lot of 5,920 sq ft (550 m²) or less, the maximum is 592 sq ft (55 m²). On larger lots it is 10% of the lot area, subject to a maximum. Confirm the current cap with City zoning staff before you design to it.
Do I need extra parking for a garden suite in Mississauga?
No. Additional parking spaces are not required for an attached or detached additional residential unit. Your lot may still have only one driveway.
Can I rent out a Mississauga garden suite?
Yes, a legally permitted garden suite can be rented. It cannot be severed and sold separately from the main house, and a home occupation is not permitted inside it.
Are Mississauga’s pre-approved garden suite plans free?
The City publishes pre-approved studio and one-bedroom garden suite drawings at no cost. You still need a site plan and a grading plan for your property, and the drawings only suit some lots.
How close to the property line can a garden suite go?
A single-storey suite needs 2 ft (0.6 m) to an interior side lot line and 5 ft 11 in (1.8 m) to the rear. A two-storey suite needs 5 ft 11 in (1.8 m) on both. Exterior side lot lines need 8 ft 2 in (2.5 m) for one storey and 14 ft 9 in (4.5 m) for two.
Sources
- City of Mississauga Zoning By-law 0225-2007, as amended, Table 4.1.1.14 (Detached Additional Residential Unit), introduced by By-law 0174-2023.
- City of Mississauga, Additional Residential Units, mississauga.ca.
Verified against the by-law on 21 October 2026. Zoning changes. The maximum floor area cap on larger lots, and any 2026 amendments to these provisions, should be confirmed with City of Mississauga zoning staff at 905-615-4311 before you commit to a design.
Figures are for detached additional residential units in Mississauga and do not apply in Oakville or Burlington, which have their own standards.
Building in Oakville instead? See our Oakville and Burlington garden suite page and the 2026 Oakville garden suite rules.
