Bannock County, ID Fence Regulations: Retaining Walls (2026)

The Bannock County Board of County Commissioners administers this standard through the floodplain administrator, a role assigned jointly to the County Engineer and the planning and development director under Section 14.04.150. Before a homeowner or contractor builds a retaining wall in a designated special flood hazard area, Section 14.04.170 requires a floodplain development permit application that includes a plot plan showing the boundary of the floodway and the base flood elevation. If the wall sits inside the regulated floodway itself, Section 14.04.210(J)(2) sends the project to the tougher floodway test in Section 14.04.240(A): no encroachment, including fill placed for a retaining wall, is allowed unless a registered professional engineer certifies through hydrologic and hydraulic analysis that the wall will not raise base flood levels, or unless FEMA has approved a conditional letter of map revision.

Outside the floodway but still within the special flood hazard area, the general standards of Section 14.04.200 still apply, requiring flood-resistant materials and anchoring against flotation and lateral movement. If the floodplain administrator finds a retaining wall built without the required permit or certification, Section 14.04.180 requires written notice to the owner, a hearing within ten days, and a corrective order giving sixty to one hundred eighty days to remedy the violation, shortened if there is imminent danger to life or property. An owner may appeal a corrective order to the Bannock County Commissioners within ten days of the order; without an appeal, the floodplain administrator's order becomes final.