Garden Suite Permit Requirements in Ontario: Complete 2026 Guide

What Is a Garden Suite in Ontario?

A garden suite (also called a backyard home, granny flat, or additional dwelling unit) is a self-contained residential unit located in the rear yard of a property with an existing house. Under Ontario's Bill 23 (More Homes Built Faster Act, 2022), municipalities are required to permit garden suites on lots with residential dwellings, subject to certain conditions.

A garden suite is different from a laneway suite (which fronts on a public lane) and a basement apartment (which is within the existing house). Garden suites are standalone structures with their own entrance, kitchen, bathroom, and living space.

Bill 23: What Changed for Garden Suites

Bill 23, which received Royal Assent on November 28, 2022, made several significant changes that make garden suites easier to build across Ontario:

• Municipalities must allow up to 3 residential units per lot (main house + basement apartment + garden suite) • Municipal site plan control cannot be applied to garden suites of up to 3 units • Development charges are waived for additional dwelling units (including garden suites) created within existing residential properties • Parkland dedication fees are waived for additional dwelling units • Municipalities cannot require more than one parking space per additional dwelling unit

These changes apply province-wide, though individual municipalities may have specific implementation details.

Garden Suite Size and Design Requirements

While Bill 23 requires municipalities to allow garden suites, there are still design and size requirements that vary by municipality:

Garden Suite Permit Process

Building a garden suite requires a building permit from your municipality. The typical process is:

1. Pre-consultation: Contact your municipal building department to confirm requirements for your specific property 2. Design: Hire an architect or designer to prepare construction drawings 3. Site plan: Prepare a site plan showing the garden suite location, setbacks, and grading 4. Building permit application: Submit drawings, site plan, and application form 5. Review: Municipality reviews for OBC compliance and zoning conformity (typically 15–30 business days) 6. Permit issuance: Once approved, you can begin construction 7. Inspections: Multiple inspections during construction (footings, framing, insulation, final) 8. Occupancy: Final inspection and occupancy permit

Note: If your property is in a conservation authority regulated area, you'll also need a conservation authority permit, which should be applied for concurrently.

Garden Suite Costs in Ontario

The total cost of building a garden suite in Ontario typically ranges from $150,000 to $400,000+, depending on size, design, and location:

• Construction: $200–$400 per square foot ($150,000–$300,000 for a typical 600–750 sq ft suite) • Architectural/engineering fees: $5,000–$15,000 • Building permit fees: $1,000–$5,000 • Development charges: Waived under Bill 23 for additional dwelling units • Servicing connections: $5,000–$20,000 (water, sewer, electrical) • Landscaping/site work: $5,000–$15,000

The development charge waiver under Bill 23 saves homeowners $20,000–$80,000+ depending on the municipality, making garden suites significantly more financially viable.

How PermitSnapshot Helps with Garden Suites

Before investing in architectural drawings, run a PermitSnapshot report for your property. In under 5 minutes, you'll know:

• Whether your property's zoning allows a garden suite • Required setbacks and how much buildable area you have in your rear yard • Whether your property is in a conservation authority regulated area • Applicable fees and charges (with Bill 23 exemptions noted) • Any heritage designations or special overlay zones that may affect your project • Maximum permitted size and height for a garden suite on your lot

This $49 report can save you thousands in architectural fees by confirming feasibility before you start the design process.