Wayne County, MI Accessory Structures: ADU Rules (2026)

Michigan does not have a statewide law requiring cities to permit accessory dwelling units (ADUs) the way California, Oregon, and Washington do. As a result, ADU rules in Wayne County, Michigan are determined entirely by each of the 43 municipalities. Detroit revised its zoning ordinance in 2021 to permit ADUs (called accessory dwelling units or coach houses) in most residential zones, with size capped at 800 square feet or 33 percent of the primary dwelling (whichever is smaller), owner-occupancy required on the lot, and standard setback and height limits. Dearborn, Hamtramck, and Ferndale-adjacent suburbs allow limited ADUs, often restricted to attached in-law suites or detached structures on larger lots. Many Wayne County suburbs including Livonia, Westland, Taylor, and Canton Township prohibit ADUs outright or require a special use permit with public hearing. Short-term rental (STR) use of an ADU is subject to additional local regulation, with Detroit requiring STR registration. Utility connections typically require a separate water and sewer meter or shared-meter agreement with DWSD or the local utility.