Ontario’s More Homes Built Faster Act (2022) requires municipalities to allow up to three residential units on many lots — for example a basement apartment, a garden suite, or an in-law suite — subject to Building Code and servicing. Municipal zoning by-laws set the detailed standards: maximum unit size, parking, separate entrances, and servicing requirements. In rural areas on private septic systems, servicing capacity often limits what is possible. Some Durham municipalities publish ARU guides or pre-approved plans, and a few license or register second units, so check whether registration is required where you live. Fire separation, egress windows and ceiling heights are common Building Code issues in conversions. Verify requirements with the municipality before applying or building.
Additional dwelling units
This guide describes a research path — it does not decide what is allowed on a property. Confirm exceptions and amendments with the municipality.