Bonneville County, ID Environmental Rules: Flood Zones (2026)

Section 154.07, 'Basis for Establishing the Areas of Special Flood Hazard,' adopts by reference the special flood hazard areas identified in the 'Flood Insurance Study (FIS) for Bonneville County, Idaho,' dated April 2, 2002, along with its accompanying flood insurance rate maps (FIRM) or digital flood insurance rate maps (DFIRM). Those maps and the underlying study are kept on file at the County Planning and Zoning Office at 683 N Capital Ave, Idaho Falls, and they define exactly which unincorporated parcels fall inside a mapped flood hazard area.

Section 154.08 bars locating, extending, converting, altering or developing any structure or land within the chapter's scope without full compliance, and § 154.27 translates that into a permit step: a floodplain development permit is required before any development activity begins within a special flood hazard area. Under § 154.28, the applicant submits a scaled plot plan to the Floodplain Administrator showing the nature, location, dimensions and elevations of the proposed development, among other required details, before the county acts on the application. The Floodplain Administrator, whose duties are set out in § 154.26, reviews the application against the chapter's general and specific standards in §§ 154.45 and 154.46. Because § 154.09 makes the chapter's rules a floor rather than a ceiling, a stricter local or state requirement still controls where the two conflict. A property owner denied a permit, or seeking relief from a standard, can request a variance under § 154.30.