Pocatello, ID Environmental Rules: Flood Elevation Requirements (2026)

Pocatello City Code chapter 15.32, the Flood Damage Prevention Ordinance, defines flood protection elevation (FPE) in section 15.32.050 as the base flood elevation plus two feet of freeboard, or, where no BFE has been determined, at least two feet above the highest adjacent grade. Section 15.32.120 applies that standard: new construction, substantial improvements, and development of any residential structure, including manufactured homes, must have the lowest floor, including any basement, elevated no lower than the FPE. Non-residential structures face the same elevation floor, but Zones A, AE, AH, and AO allow floodproofing to the FPE instead, provided all areas below FPE are watertight with walls substantially impermeable to water and components able to resist hydrostatic and hydrodynamic loads; a registered professional engineer or architect must certify the floodproofing to the Floodplain Administrator under section 15.32.080C.

New and replacement manufactured homes must have their lowest floor no lower than the FPE, be anchored to resist flotation and lateral movement, and if the chassis elevation exceeds thirty six inches above grade, an engineering certification is required. Additions to pre-FIRM structures that qualify as substantial improvements, together with the existing structure, must meet new-construction standards; the same forty nine percent cumulative-cost-over-five-years test under section 15.32.120D.4 triggers full compliance for repairs and remodels. The Floodplain Administrator, appointed under 15.32.050, reviews applications for the Floodplain Development Permit required by section 15.32.080 before any development begins in a special flood hazard area, checking BFE, flood zone designation, and floodway boundaries on the FIRM.