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ADU Builders in Ontario
Serving 30 municipalities across the Greater Toronto Area - design, permits and construction.
30
Cities Served
9.0M+
Population Covered
Free
Site & Zoning Review
ADU Builders Services in Ontario
GTA ADU Builders provides adu builders across 30 cities in Ontario. Whether you're in Toronto, North York, or Mississauga, we offer same-day delivery, professional setup, and regular maintenance.
All Cities in Ontario
Frequently Asked Questions
Everything you need to know about our services.
We work across the 30 municipalities of the Greater Toronto Area - from Toronto, the largest at 2,794,356 residents, out to the rural townships of Durham and York. Each municipality has its own page with that city's approval band, frost depth, building season and neighbourhood coverage.
Related service: Accessory Dwelling Units
Bill 23 (More Homes Built Faster Act, 2022) requires Ontario municipalities to permit up to three residential units as-of-right on most lots already holding a detached, semi-detached or townhouse dwelling on full municipal services. The provincial framework is O. Reg. 299/19 on additional residential units, amended November 2024, with O.
Reg. 462/24 harmonising municipal by-laws against province-wide garden-suite criteria. Construction follows the Ontario Building Code, with energy compliance filed under SB-10 and SB-12.
Related service: Secondary Suites
Municipal approval costs run from $5,500-$10,000 including Brampton registration and Peel charges in Brampton to $9,000-$16,000 including Peel Region and septic permit charges in Caledon, quoted separately from construction. Regional charges (Peel, York, Durham, Halton) are the main reason the bands differ, and rural townships add a septic capacity permit on top.
Related service: Our ADU services
On a 700 sq ft reference unit, a detached garden suite estimates between $268,000-$359,500 and $281,500-$377,000 depending on the municipality, while a basement or secondary suite runs $91,000-$147,500 to $95,500-$155,000. The per-municipality difference tracks approval fees, frost depth and annual snow load - all published on each city's page.
Related service: Garden Suites
They can. Since 1 April 2024 the amended Conservation Authorities Act requires sign-off from the relevant authority - TRCA, Credit Valley, LSRCA, Kawartha or CLOCA depending on the watershed - for units inside regulated areas. Ravine, valley-land, Oak Ridges Moraine and Niagara Escarpment lots carry a real scheduling risk, so we screen for it before design begins.
Related service: Our ADU services
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Get a free, no-obligation quote from GTA ADU Builders - zoning review, permit drawings and construction for ADUs across the GTA.