Iron County, UT Environmental Rules: Flood Elevation Requirements (2026)

Section 15.12.170(A) sets the elevation standard for the county's mapped flood hazard areas: wherever base flood elevation data has been provided under Section 15.12.060 or Section 15.12.130(B), new construction and substantial improvement of any residential structure must have the lowest floor, including a basement, elevated to or above the base flood elevation, per Section 15.12.170(A)(1). Inside an AO or AH zone on the Flood Insurance Rate Map, where the flood depth is shallow and unpredictable rather than mapped to a fixed elevation, Section 15.12.170(A)(2) instead measures up from the highest adjacent grade: the lowest floor has to sit at least as high as the depth number printed on the map, or at least two feet if the map does not list a specific depth.

Within Zones AI and AH, Section 15.12.170(A)(3) also requires adequate drainage paths around structures built on slopes so floodwaters are guided around and away from the building rather than pooling against it. The commission chairman records the actual elevation of the lowest floor of every new or substantially improved structure, and whether it has a basement, under Section 15.12.130(C)(1), creating a permanent parcel-level record the county can check if a later addition or repair is proposed. Manufactured homes follow their own anchoring and elevation track under Section 15.12.170(C), and anyone seeking relief from these elevation standards has to go through the variance procedure before the appeals hearing officer under Section 15.12.140.