Frederick County, VA Environmental Rules: Flood Zones (2026)

Chapter 165, Article V, Part 503 establishes the Frederick County Floodplain Overlay District under authority of Code of Virginia §§ 15.2-2200, 15.2-2280 and 15.2-2283. Under § 165-503.13.A, every use, activity and development in any floodplain district, including placement of manufactured homes, needs a permit, and even where a permit is not required the Zoning Administrator must approve the activity first. No development may adversely affect the flood-carrying capacity of any channel, watercourse, drainage ditch or drainage facility. Permit applications must show the base flood elevation at the site, the elevation of the lowest floor for structures to be elevated, and topographic information on existing and proposed grades, per § 165-503.13.B.

The construction standard in § 165-503.15.A(1) requires new construction or substantial improvement of a residential structure, including manufactured homes, in Zones A1-30, AE, AH and A with detailed base flood elevations to have its lowest floor, including any basement, elevated no lower than one foot above the base flood elevation; nonresidential buildings face the same elevation standard or may be floodproofed instead under § 165-503.15.A(2), certified by a registered professional engineer or architect. Accessory structures in the special flood hazard area are capped at 600 square feet, must use flood-resistant materials below the base flood elevation, and need flood openings sized at one square inch per square foot of enclosed area.

Existing structures must be brought into conformity with Part 503 when substantially repaired or improved, per § 165-503.16.A, unless the Floodplain Administrator finds the work is not a substantial improvement and adds no noncompliant square footage.