Washington County, MN Accessory Structures: Garage Conversions (2026)

Chapter Two Section 1.1(11) of the Washington County Development Code states plainly that "the use of a cellar, garage, recreational vehicle, trailer, basement with unfinished exterior above or accessory building as a dwelling unit is prohibited." The rule sits inside the General Standards that apply countywide to every zoning district in unincorporated Washington County, meaning a detached garage, pole building or other accessory structure cannot legally be finished out and occupied as a bedroom, apartment or full-time residence, regardless of lot size or district. Any change to a structure's use, occupancy or exterior still requires a Certificate of Compliance from the County Zoning Administrator confirming the proposed use matches an approved Development Code use; a request to occupy a garage as living space would be reviewed against Section 1.1(11) and denied outright.

Property owners in the Shoreland Management Overlay District or the St. Croix River Management Overlay District face the added requirement of Section 1.2(1), which mandates a building permit for the accessory structure itself before any interior work begins. This provision governs unincorporated townships only; Stillwater, Woodbury, Oakdale, Cottage Grove, Forest Lake and the county's other cities regulate accessory-structure occupancy under their own municipal codes, not this county ordinance.