Richmond Hill: local suite starting point
Richmond Hill requires a building permit for an Additional Residential Unit and publishes zoning rules plus a pre-approved detached ARU model that still requires a site-specific site plan.
Open the official Richmond Hill source ↗The broader Greater Toronto Area housing pattern does not replace the Richmond Hill approval file. Confirm this address and unit type with the local source.
Ontario: the provincial layer
On identified Ontario residential lands, the provincial ARU framework generally allows three units within the main house, or two in the main house plus one ancillary unit. Local zoning standards such as height and setbacks remain relevant.
Ontario additional residential unit framework ↗Use this order before committing to a design
What kind of unit?
Identify whether the proposal is an internal suite or a detached ADU before using any checklist or setback rule.
Is the use allowed?
Separate entitlement from construction. The city may allow another unit in principle while still regulating its size, location or form.
Can the building comply?
Use the applicable code route to verify life-safety, ventilation, exit and structural requirements before finalizing the design. For this Richmond Hill project, tie that check back to the current local approval path.
Can the site serve it?
For backyard or garden units, test the site for setbacks, access, servicing and utility capacity before finalizing the footprint.
How to sequence a Richmond Hill suite project
A good sequence is property eligibility, unit type, building design, utilities/trades and inspections. Starting with finishes can hide the expensive constraints.
For an existing unit, request the municipal permit history and any final inspection or occupancy record. Present use alone does not prove approval.
Official sources
Reviewed 2026-09-14. Confirm both the local land-use path and the current provincial building requirements before construction.