5 county-level rules, plus city-specific rules for 3 cities in Rock County, Wisconsin.
Verified from official government sources
Wisconsin has no statewide ADU mandate. Rock County only zones consenting unincorporated towns under Wis. Stat. 59.69; inside Janesville, Beloit and villages, ADU rules are municipal. Confirm with your town or city before adding an in-law unit.
In Rock County's unincorporated towns, accessory buildings like sheds must meet the district's yard setbacks. In the Town of Union's A-1 district, accessory buildings need a 10-foot side setback and buildings top out at 35 feet.
Town of Union (Rock County) Zoning Ordinance ch. 17, A-1 District dimensional standards
Minimum Side Yard Setback: Principal Buildings 20 ft. on each side; Accessory Buildings 10 ft. on each side. Maximum Building Height 35 ft.
Rock County has no single garage-conversion ordinance. Turning a garage into living space creates a dwelling unit subject to your town, village or city zoning plus the Wisconsin Uniform Dwelling Code for habitable-space standards.
A carport is an accessory structure. Rock County sets no separate carport ordinance; it must meet your town, village or city zoning setbacks and, in county-zoned towns, the location and height limits under Wis. Stat. 59.69.
Town of Union (Rock County) Zoning Ordinance ch. 17, sec. 17.04 (Building)
Building: Any structure used, designed or intended for the protection, shelter, enclosure ... garages, carports, and other attached or accessory structures.
Wisconsin has no statewide tiny-home law. Whether a tiny house is allowed in Rock County depends on your town, village or city zoning and whether it sits on a permanent foundation meeting the Wisconsin Uniform Dwelling Code.
3 cities in Rock County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
See every category we cover for Rock County — parking, noise, fences, fires, animals, pools, and more.
Rock County Ordinance Hub →