Bannock County, ID Environmental Rules: Flood Elevation Requirements (2026)

Section 14.04.060 of the Bannock County Municipal Code defines 'flood protection elevation (FPE)' as the base flood elevation plus the freeboard, and it fixes that freeboard at 2.0 feet: where a base flood elevation (BFE) has been determined, the FPE is the BFE plus 2.0 feet, and where no BFE has been established, the FPE is at least 2.0 feet above the highest adjacent grade. Section 14.04.210(A) then applies that standard to residential building: new construction, substantial improvements and development of any residential structure, including manufactured homes, must have the lowest floor, including basement, elevated no lower than the flood protection elevation.

The same section extends the rule to non-residential structures, which may either meet the same elevation or be floodproofed to it, and to manufactured homes, which must have their lowest floor at or above the FPE and be anchored to a certified foundation system, with an engineering certification required when the chassis sits more than 36 inches above grade. Section 14.04.170(A) requires the elevation of a structure's proposed lowest floor, in relation to mean sea level, to be submitted with the floodplain development permit application, and Section 14.04.170(C) calls for post-construction elevation certification.

Where FIRM data specifies a flood depth number instead of a BFE, Section 14.04.250 sets a separate, lower one-foot freeboard standard above the highest adjacent grade for structures in those areas. Building below the required elevation without a permit is a misdemeanor under Section 14.04.140, punishable by up to a $300 fine, up to 180 days in jail, or both.