Wisconsin Uniform Dwelling Code Preempts Tiny Home Standards

Under Wis. Stat. 101.63 and 101.65, the Department of Safety and Professional Services administers the Uniform Dwelling Code, which applies statewide to new one- and two-family dwellings. Tiny homes built on permanent foundations are treated as dwellings and must meet UDC structural, electrical, plumbing, HVAC, and energy requirements. Towns, villages, and cities cannot adopt building code standards that conflict with or exceed the UDC for these structures. Tiny homes on wheels are regulated as recreational vehicles or manufactured homes under separate state rules. Zoning, lot size, and minimum dwelling-size standards remain a local issue and are not preempted, so siting still depends on municipal zoning.

Building a tiny home without meeting UDC standards or obtaining required state-approved permits can result in stop-work orders, fines, and required removal or remediation by local UDC inspectors.