Niagara ADU Guide
This starter page gives you a more detailed information hub similar to larger ADU websites, but written for Niagara and Ontario conditions. Edit this page freely to match your exact sales and permitting process.
What is an ADU?
An accessory dwelling unit is a self-contained residential unit located on the same lot as a principal dwelling. Depending on the municipality, that can include a basement suite, an addition, a converted garage, or a detached garden suite.
Niagara Falls basics
- Building permits are required for any ADU project.
- For accessory-building ADUs, the City notes a maximum lot coverage allowance up to 93 square metres where zoning conditions are met.
- Urban detached ADUs cannot exceed 6 metres in height, with 4.5 metres to the top of walls and supporting posts.
St. Catharines basics
- Detached ADUs are permitted in residential zones, subject to property-specific rules.
- A building permit is required and submissions include construction drawings and a site plan.
- The City notes parking requirements of one space for one ADU and one space for two ADUs, plus one space for the principal dwelling.
Funding and incentive angle
St. Catharines published an ADU grant program that covered up to 70% of eligible costs, with stated maximums of $40,000 for interior units and $80,000 for exterior units, but the City also notes 2025 funding was depleted. You can keep this section updated as programs change.
Why this matters for Niagara homeowners
Municipal rules are similar in direction but not identical in detail. That is why a Niagara-specific website should explain feasibility, servicing, approvals, and project type in plain language instead of making blanket promises.