ADU Rules in Hot Springs, South Dakota

Hot Springs is the county seat of Fall River County in the southern Black Hills of South Dakota, with a population of approximately 3,700 residents. The city sits at an elevation of about 3,400 feet and is renowned for its natural mineral hot springs — warm waters that drew Native Americans to the area for centuries and later attracted late 19th-century resort development that gave the city its distinctive sandstone architecture along Battle Mountain. Today Hot Springs is a tourist and retirement destination known for its natural beauty, historic downtown, and unique geological heritage.

The city is home to the Mammoth Site, a world-class active paleontological excavation where the bones of more than 60 Columbian and woolly mammoths have been uncovered in a preserved sinkhole deposit — one of the most significant mammoth fossil sites in the world and a major attraction for visitors to the Black Hills region.

State Law Context

South Dakota has no statewide ADU law requiring municipalities to permit accessory dwelling units. ADU permissibility in Hot Springs is determined by:

• Hot Springs' municipal zoning ordinance
• Your property's zone classification
• Any conditional use permit or variance procedures available under local code

Contact the Hot Springs City Planning and Zoning Office for current, accurate information. As a smaller city, Hot Springs may have less complex zoning code than larger South Dakota communities, but rules should be confirmed directly with the city.

ADU Types That May Be Permitted

Subject to Hot Springs' zoning ordinance, potential ADU configurations may include:

• Accessory apartment / in-law suite: A secondary unit within or attached to the primary dwelling — common in the city's historic homes.
• Detached secondary dwelling: A freestanding structure on the same lot, subject to setback and coverage requirements.
• Carriage house or outbuilding conversion: Converting an existing accessory structure to a habitable unit.

Hot Springs has a stock of late-Victorian and early 20th-century homes, many built from local Sioux Falls Red Quartzite sandstone, that can lend themselves well to interior conversion ADUs. The city's tourist economy also means ADUs can serve as short-term rental accommodations (subject to any local short-term rental regulations).

Fall River Flood Zones

The Fall River (a natural warm-water stream fed by the hot springs) flows through the heart of Hot Springs, and portions of the city along the river corridor may fall within FEMA-mapped flood zones. Flooding has historically affected lower-lying areas near the river. Key considerations:

• FEMA Zone AE: Areas with detailed base flood elevation data where elevation requirements apply to new construction.
• Floodplain management: New structures in flood zones must comply with Hot Springs' local floodplain ordinance.
• Flood insurance: Required for federally backed mortgages on properties in mapped flood zones.

Check FEMA's Flood Map Service Center using your specific parcel address before finalizing ADU plans for a Fall River-adjacent property.

Black Hills Terrain and Topography

Hot Springs sits in rugged Black Hills terrain with steep slopes, variable soils, and rock outcrops. Construction considerations specific to this area include:

• Sloped lots: Many Hot Springs properties are on grades that require engineered foundations or retaining walls for additions or detached structures.
• Rock outcrops: Shallow bedrock can significantly increase excavation costs for basement or underground utility work.
• Wildland-Urban Interface (WUI): Some properties at the edge of the city may be in WUI zones with fire defensible space requirements that affect ADU siting.

Tourist Economy and Short-Term Rentals

Hot Springs' tourism-based economy may make short-term rental of an ADU attractive. However, confirm with the City of Hot Springs whether short-term rentals (Airbnb/VRBO) require a separate license or are subject to any zoning restrictions, as these rules are separate from ADU permissibility.

Permit Process

1. Zoning inquiry — Contact Hot Springs Planning and Zoning to confirm ADU eligibility for your zone and parcel.
2. Flood zone check — Review FEMA flood maps for Fall River flood zone exposure.
3. Site assessment — Consider a consultation with a local contractor about slope, soil, and bedrock conditions.
4. Building permit application — Submit plans to the Hot Springs Building Official under the South Dakota State Building Code.
5. Inspections and certificate of occupancy — All required inspections must be completed.

Contact Information

• City of Hot Springs Planning and Zoning: (605) 745-5135 | cityofhotsprings.org
• Hot Springs Building Official: Contact through City Hall
• Fall River County Commission: (605) 745-5130
• FEMA Flood Map Service Center: msc.fema.gov

Disclaimer

Zoning and floodplain regulations change. Always verify current ADU rules directly with the City of Hot Springs Planning and Zoning Office and Building Official before purchasing property, hiring a contractor, or beginning construction. This page provides general information and does not constitute legal or land-use advice.