Sioux Falls, SD Accessory Structures: ADU Rules (2026)
ADU rules in Sioux Falls, SD, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Max ADU size
- 40% of principal building's square footage
- Location
- Rear yard only, 10 ft from house
- Parking
- Two additional off-street spaces required
- Occupancy
- Primary home or ADU must be owner-occupied
- Applies in
- RS, RD-1, RD-2, RA-1, MH districts (DD2)
Summary
Sioux Falls allows one detached accessory dwelling unit per single-family lot as a permitted special use, capped at 40% of the primary home's size, in the rear yard only, with owner-occupancy and parking requirements.
(4) Accessory dwelling units—detached. A. Only one additional single-family dwelling unit is allowed and one of the units must be owner-occupied. B. A minimum of two off-street parking spaces are required. C. The detached accessory dwelling units have the following standards: 1. The unit must not be any more than 40% of the square feet of principal building not including the garage. 2. The unit is only allowed in the rear yard. 3. The unit must be at least ten feet from the main dwelling.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-135: Current through local ordinance 54-26, passed 7-14-2026).
Full Breakdown
Sioux Falls treats a detached ADU as a "permitted special" accessory use under the DD2 form (RS, RD-1, RD-2, RA-1, and MH zoning districts): staff can approve it administratively once it meets the § 160.073 standards, with no public hearing required. Only one extra dwelling is allowed per lot, and either the primary house or the ADU must be owner-occupied. The unit can't exceed 40% of the principal building's square footage (garage excluded), must sit in the rear yard at least ten feet from the main house, match the main building's required yards, and the property needs two additional off-street parking spaces. A design that can't meet those standards has to go through a discretionary conditional use permit instead.
Violations & Fines
Building without the required zoning permit, exceeding the 40% size cap, skipping the extra parking spaces, or placing the unit outside the rear yard can draw a stop-work order and force removal or reconfiguration by Planning and Building Services.
Frequently Asked Questions
Do I need a public hearing to build a detached ADU in Sioux Falls?
How big can a detached ADU be in Sioux Falls?
Sources & Official References
Other rules in Sioux Falls
How Sioux Falls compares: Easiest Cities to Build an ADU·Compare Sioux Falls to another location·View the South Dakota accessory structures overview
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