DeKalb County, GA Environmental Rules: Flood Elevation Requirements (2026)

DeKalb County Code Article IV, Division 5, § 14-432 sets the freeboard standard for every parcel inside the county's mapped future-conditions floodplain in the unincorporated area (cities such as Decatur, Dunwoody, Brookhaven, Tucker, Stonecrest, Chamblee, Doraville, Clarkston, Avondale Estates, Lithonia, Pine Lake, Stone Mountain, and the DeKalb sliver of Atlanta enforce their own floodplain codes). Under § 14-432(a), no principal building, including a manufactured home, may be built or substantially improved within the future-conditions floodplain unless it meets every pertinent requirement of Article IV. Section 14-432(b)(3)a requires residential lowest floors, including basements, elevated no lower than three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher, once the engineering study standards of §§ 14-430, 14-431 and 14-442 are satisfied.

Non-residential structures under § 14-432(b)(3)b may instead be floodproofed watertight to one foot above base flood elevation, with a registered engineer or architect certifying the design to the floodplain coordinator. Section 14-410 defines "base flood elevation" as the highest water surface anticipated at a given point during the base flood, and "future-conditions flood elevation" as a standard equal to or higher than that base elevation. Section 14-432(b)(1)-(2) further requires anchoring against flotation or lateral movement and flood-resistant construction materials per FEMA Technical Bulletin TB 2-93, with HVAC, electrical, ventilation and plumbing components set three feet above base flood elevation or one foot above the future-conditions elevation, whichever is higher.

Enclosed areas below the lowest floor used only for parking, access or storage must have flood vents totaling at least one square inch per square foot of enclosed area, with openings no higher than one foot above grade. A variance from these elevation standards is rare: § 14-444(b) states variances "are quite rare" because the board of commissioners must protect residents from flood loss, and § 14-447 routes requests to the zoning board of appeals after a written application filed within 30 days.