Stearns County, MN Accessory Structures: ADU Rules (2026)

1 governs attached Accessory Dwelling Units (ADUs): no more than one per lot, and none at all if the lot already carries a temporary or secondary single-family unit. The ADU cannot be sold separately from the principal dwelling or placed on its own tax parcel, sewage treatment must be sized for the combined bedroom count, and the applicant must submit a floor plan and elevation drawing with the building permit application. Critically, an attached ADU cannot exceed 40 percent of the principal dwelling's finished floor area, excluding the attached garage, and decks, patios and unenclosed roof overhangs do not count toward that cap.

2 governs detached ADUs under the same one-per-lot and no-separate-sale rules, but sets its own size band: gross floor area, including any attached garage, must be at least 150 square feet and no more than 1,000 square feet. 2, must meet every applicable setback including the animal feedlot setback, must sit at least 10 feet from the principal dwelling, and must use the existing driveway access unless the road authority approves otherwise. 33. Manufactured homes may serve as detached ADUs in the Agricultural and Transitional Districts but are flatly prohibited as ADUs in the Residential Districts. 12(B).