Sioux Falls, SD Accessory Structures: Garage Conversions (2026)

Sioux Falls Code of Ordinances § 159.305 (Accessory Dwelling Units) is the controlling section for converting a garage into independent living space with a kitchen, bath, and separate entrance. Only one ADU is allowed per parcel and only in zoning districts where § 159.305 permits it (most single-family residential districts under the Shape Sioux Falls 2040 zoning code). For an attached ADU (e.g., converted attached garage), the ADU's finished floor area cannot exceed 75% of the primary dwelling's finished floor area; for a detached ADU (converted detached garage), the cap is 50%. Two additional off-street parking spaces must be provided for the ADU on top of the parking required for the primary dwelling. One of the units (main home or ADU) must be owner-occupied. A detached ADU in the required rear yard must sit at least 7 ft from side and rear property lines. The conversion itself requires a building permit, plus separate electrical, plumbing, and HVAC permits. Garage conversions that DO NOT add a kitchen or separate entrance (e.g., extra bedroom, family room) are treated as interior remodels under Sioux Falls Code Title 150 (Building Code, adopting the 2021 IRC) — building permit required, but the ADU floor-area and parking caps do not apply. Egress windows, ceiling height (7 ft minimum under IRC), smoke and carbon-monoxide alarms (SDCL Chapter 34-45), and energy code compliance all apply. South Dakota has NOT enacted a statewide ADU preemption — Sioux Falls' ADU framework is entirely a creature of the city's home-rule charter under SDCL Chapter 6-12.