Raleigh, NC Environmental Rules: Flood Elevation Requirements (2026)

Raleigh's Unified Development Ordinance sets a locally enhanced flood-elevation standard that goes beyond the bare federal base flood elevation. Sec. 3, unless the lowest floor, including any basement, and all mechanical, electrical, heating, ventilation and air conditioning equipment sits at or above the regulatory flood protection elevation. A registered professional engineer or architect must certify on the building plans that everything below that elevation can withstand the depth, pressure, velocity, impact and uplift forces of a 100-year flood, and a registered land surveyor must certify the as-built lowest-floor elevation to the nearest tenth of a foot before occupancy.

Nonresidential structures and residential accessory structures get an alternative: full dry floodproofing certified by a professional engineer or architect in place of elevation. 2's Defined Terms section spells out how that elevation is calculated: the regulatory flood protection elevation equals the base flood elevation shown in the Flood Insurance Study for Wake County plus 2 additional vertical feet of freeboard, or, outside mapped areas, a topographic contour 5 vertical feet above flood hazard soils. The requirement doesn't apply to work correcting existing code violations that's the minimum needed for safe living conditions, or to reconstruction of structures listed on the National Register of Historic Places that keeps their historic designation.