Frederick, MD Environmental Rules: Flood Elevation Requirements (2026)

Frederick calculates its base flood elevations from the Flood Insurance Study for Frederick County, Maryland dated September 19, 2007, and the accompanying FEMA Flood Insurance Rate Maps, kept on file at the City's Engineering Division at 140 W. Patrick Street, per § 31-3. City Code § 31-7(20) defines 'flood protection elevation' as the base flood elevation plus 2 feet of freeboard, the extra safety margin every elevated structure must clear. Under § 31-31(b), new residential structures and residential portions of mixed-use buildings must have their lowest floor, including any basement, built at or above that flood protection elevation; in Zone AO shallow-flooding areas, the floor instead must sit above the highest adjacent grade by the FIRM's depth number plus 2 feet, or at least 4 feet if no depth number is listed.

Basement floors that sit below grade on every side are prohibited outright, whether the structure is residential or nonresidential under §§ 31-31(a) and 31-32(c). Nonresidential buildings that are floodproofed instead of elevated must be watertight to the flood protection elevation plus an additional foot under § 31-32(d). Section 31-19(b)(5) separately requires the electric panelboard in any structure located in a special flood hazard area to sit at least 3 feet above the base flood elevation. 2% annual chance) flood elevation, whichever is highest.