Who qualifies for a Mississauga garden suite
Detached homes, semi-detached homes, and eligible townhomes can add one garden suite per lot. Townhome eligibility is narrower — corner and through lots in RM5 and RM6 zones typically qualify; standard interior condo townhouses generally do not.
One garden suite per lot. A basement or in-house second unit doesn't block you from also adding a garden suite (Mississauga permits up to three units per lot including the primary dwelling).
The core rules
- Rear setback: 1.8 m minimum from the rear lot line.
- Interior side setback: 0.6 m minimum.
- Street-facing side setback (corner lots): 2.5 m minimum.
- Fire route: 1.2 m wide × 2.1 m high clear path from the street to the suite's entrance door, no greater than 45 m in length.
- Height and size: capped per the ARU by-law — the pre-approved Studio (430 sq ft) and One-Bedroom (600 sq ft) are both designed to comply.
- Separate municipal address: required for the new unit ($81.90 + HST).
The 7-step permit process
- Feasibility & zoning check. Confirm your zoning, lot dimensions, and setbacks. Use our instant zoning checker to get an immediate readout.
- Choose pre-approved or custom design. Studio 430 and One-Bed 600 are the free pre-approved options; custom means a designer and a longer review.
- Site plan + grading/drainage plan. Prepared by a qualified professional. Required even with pre-approved building plans.
- Building permit application in ePlans. Reference the pre-approved model number; the building plans are not re-submitted with the application.
- First review: ~15 business days for complete applications. Reviewers may return comments requiring revisions before issuance.
- Fees & charges. Permit fee is paid at issuance and refunded after final inspection. Pay the $81.90 + HST address fee. Second and third units are exempt from most development charges.
- Inspections through to occupancy. Standard building, HVAC, plumbing, and electrical (ESA) inspections. An optional kickoff meeting with Inspection Services can head off issues.
What can go wrong (and how to avoid it)
- Incomplete submissions. Missing grading details, no arborist report where required, or missing service pipe sizing — each triggers a resubmission cycle.
- Non-conformance requiring a minor variance. If your design misses a setback or height rule by a small margin, you'll need a Committee of Adjustment application — adding 2 to 4 months.
- Water service decisions. Sharing the main service is cheaper but requires the Water Service Pipe Sizing Form and adequate existing capacity. Separate service through Region of Peel adds cost and coordination but future-proofs the property.
Frequently asked questions
Not for the building design itself if you use one of the free pre-approved layouts (Studio 430 or One-Bed 600). You do still need a professional to prepare the site plan and the grading/drainage plan — these are site-specific and required for every application.
Keep reading
Disclaimer: Figures cited are market estimates provided for information only and are not a quote. Municipal rules, fees, and programs change — always verify current requirements with your local authority. Modular X provides exact pricing only after a site-specific feasibility review.