Verify locally. South Dakota has NO mandatory statewide residential building code — Sioux Falls, Rapid City, and other cities each adopt the IRC locally (2021 IRC is common). Many rural counties issue no building permits at all. Always verify with your city/county building department. ADU rules below are drawn from official sources — always confirm with the issuing building department before designing or building.
ADU permit rule
ConditionalGenerally allowedcity authority
Fee basis
Valuation-based; set by the issuing city.
Typical timeline
Plan review handled by the local building department.
Setback
—
Area threshold
Local zoning sets lot-coverage, setback, and size limits.
Exempt if
None statewide — South Dakota has no uniform ADU statute; an ADU always requires local zoning approval and a building permit where allowed.
Go / no-go
allowed
South Dakota has no statewide building code and no state ADU law. Sioux Falls and Rapid City allow ADUs by local ordinance; many rural counties have no building department at all. Zoning approval (use, setbacks, parking) is typically required before the building permit.
Do I need a permit to build an ADU in South Dakota?
Per South Dakota rules, an ADU is "conditional" for a permit and the authority is "city". South Dakota has no statewide building code and no state ADU law. Sioux Falls and Rapid City allow ADUs by local ordinance; many rural counties have no building department at all. Zoning approval (use, setbacks, parking) is typically required before the building permit. Always confirm with the issuing building department.
How big can an ADU be in South Dakota?
Area threshold: Local zoning sets lot-coverage, setback, and size limits.
What are the ADU setbacks in South Dakota?
Setback rules vary by city in South Dakota; confirm with the local planning or building department.
How much does an ADU permit cost in South Dakota?
Fee basis: Valuation-based; set by the issuing city.