Minnehaha County, SD Fence Regulations: Retaining Walls (2026)

Section 1 of the 2021 IBC Adoption Ordinance and the 2021 IRC Adoption Ordinance brought the International Building Code (2021 edition with Appendix E, G, H) and the International Residential Code (2021 edition with Appendix E, G, H) into Minnehaha County for all building permits issued after May 27, 2022. Under IBC Section 105 / IRC Section R105 a building permit is required for retaining walls over 4 feet (1219 mm) in height measured from the bottom of the footing to the top of the wall, or any retaining wall that supports a surcharge (such as a driveway, parking area, or sloped grade). Walls 4 feet or less without a surcharge are typically exempt from the permit requirement but must still comply with the County Zoning Ordinance's general lot and setback regulations. Retaining walls, concrete slabs, utility poles, and fences are NOT treated as 'structures' under the County Zoning Ordinance (Section 26 Definitions, as amended by MC16-73-05), so they are not subject to the building-setback requirements that apply to homes and garages. Engineering plans signed by a South Dakota-licensed engineer are typically required for walls over 4 feet or for walls with significant grade differential. Within the floodplain (mapped under FEMA panels and the county's 2017 Revised Flood Plain Management Ordinance), retaining walls may require additional review to avoid altering flood elevations.