1 county-level rule, plus city-specific rules for 3 cities in Waukesha County, Wisconsin.
Verified from official government sources
Waukesha County exercises county zoning under Wis. Stat. §59.69 over unincorporated towns that have adopted the county code, while incorporated cities and villages (Waukesha, Brookfield, New Berlin, Pewaukee, Mukwonago, etc.) regulate ADUs locally under Wis. Stat. §62.23(7) and §61.35. Wisconsin has no statewide ADU mandate. The Waukesha County Basic Zoning Ordinance (Appendix A, effective 12/11/2024) treats secondary residential units as accessory uses subject to district size, setback, and family-engagement standards.
3 cities in Waukesha County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
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Waukesha County Ordinance Hub →