Frederick, MD Environmental Rules: Flood Zones (2026)

Frederick's special flood hazard areas are the zones shown on the FEMA Flood Insurance Rate Maps tied to the 2007 Flood Insurance Study for Frederick County, per § 31-3, and Chapter 31's general development standards in Article III apply to every one of those areas under § 31-16. Section 31-11 requires a City Engineer permit before any development touches a flood hazard area, covering filling, grading, new construction, substantial improvement or repair of substantial damage, manufactured home placement, temporary structures, and watercourse alteration; the City Engineer, appointed as Floodplain Administrator under § 31-8, reviews each application to confirm the proposed elevation, floodproofing, and drainage meet Chapter 31 before issuing the permit, and determines whether the site needs an MDE state permit as well.

A permit expires if actual construction doesn't start within 180 days, though the Floodplain Administrator can grant written extensions if the underlying flood hazard data hasn't changed. Development that would encroach into a mapped floodway faces additional restrictions under § 31-30: the applicant must show there's no practical alternative, obtain an MDE permit, and submit engineering analysis proving the project will not raise the base flood elevation at all. Subdivisions of 5 lots or 5 acres or more inside a flood hazard area without published base flood elevations must independently determine those elevations, and subdivision access roads must be built at or above the base flood elevation under § 31-17.