Benton County, AR Environmental Rules: Flood Elevation Requirements (2026)

Sec. 38-73 sets Benton County's elevation standard for every zone A and AE parcel outside the shallow-flooding AO/AH areas. Subsection (1) governs homes: "new construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above an elevation one foot above the base flood elevation," and "a registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator" confirming the elevation. Subsection (2) gives a commercial or industrial building a second path: elevate the lowest floor the same one foot above base flood elevation, "or, together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water," with hydrostatic and hydrodynamic load resistance certified by a registered engineer or architect and recorded by the floodplain administrator.

" Recreational vehicles get a narrower carve-out under subsection (5): they escape the freeboard rule only if on site fewer than 180 consecutive days or fully licensed and ready for highway use. Sec. 38-72 layers general construction standards on top of all of this, including a flat prohibition on basement foundations in any special flood hazard area.