Wayne County, MI Accessory Structures: Tiny Homes (2026)

Michigan home-rule jurisdictions (cities and townships) control minimum dwelling size, and Wayne County does not preempt them. The 2018 IRC Appendix Q, which permits dwellings as small as 400 square feet (excluding lofts) with reduced ceiling-height and stair specifications, has not been adopted into the Michigan Residential Code statewide; LARA's Bureau of Construction Codes enforces the unmodified residential code unless a local jurisdiction has separately adopted Appendix Q. Many Wayne County municipalities (Detroit, Dearborn, Livonia, Westland, Plymouth, Northville Township, Canton, etc.) keep minimum dwelling-unit floor area in the 600 to 950 sq ft range in single-family residential districts, which makes a freestanding tiny home on its own lot effectively non-compliant without a zoning variance. A tiny home on wheels (THOW) is treated as either a recreational vehicle (occupancy limited under municipal RV ordinances and not allowed as a permanent dwelling on residential lots) or as a manufactured home subject to the Michigan Manufactured Housing Commission Act (PA 96 of 1987). HUD-Code manufactured homes generally must be sited in licensed mobile home parks or on lots that explicitly allow them. Detached ADU/accessory dwelling unit ordinances in Wayne County are limited and city-specific. Confirm minimum floor area, foundation requirements, and ADU eligibility with the host municipality, and call the Wayne County Building Department at 734-595-6504 only for unincorporated parcels.