ADU rules in Rock County, WI — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Rock County zoning under Code of Ordinances Chapter 4 (Land Use Management and Zoning) regulates accessory uses only in unincorporated areas where the County is the zoning authority under Wis. Stat. §59.69. Janesville, Beloit, and incorporated villages administer their own zoning codes. Wisconsin has no statewide ADU mandate.
Wis. Stat. §59.69 grants counties zoning authority over unincorporated towns that have adopted county zoning. Within incorporated cities (Janesville, Beloit, Edgerton, Evansville, Milton) and villages, ADU permission depends on local zoning ordinances. Town zoning ordinances such as Town of Magnolia and Town of Union also regulate accessory structures and density independently. Standards typically address minimum lot size, setbacks, owner-occupancy in some jurisdictions, and conformance with the Wisconsin Uniform Dwelling Code (Wis. Admin. Code SPS 320-325) for any new dwelling unit. Property owners should confirm jurisdiction with the Rock County Planning, Economic and Community Development Department before applying.
Zoning violations under Wis. Stat. §59.69(11) carry forfeitures set by ordinance, plus daily continuing violation penalties. Unpermitted dwelling units may require removal or after-the-fact permits.
Rock County, WI
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Rock County, WI
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Rock County, WI
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Rock County, WI
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Rock County, WI
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Rock County, WI
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See how Rock County's adu rules rules stack up against other locations.
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