Charles County, MD Environmental Rules: Flood Elevation Requirements (2026)

Chapter 238's definitions section, § 238-6, defines FLOOD PROTECTION ELEVATION as the base flood elevation plus two feet of freeboard unless the article notes otherwise, explaining that freeboard is a factor of safety compensating for uncertainty in what could push flood heights above the calculated level for a selected flood, including wave action, obstructed bridge openings, debris and ice jams, climate change, and the hydrologic effect of urbanization in a watershed. That two-foot freeboard standard is what new construction is actually held to: under § 238-9D(1)(a), for residential structures and residential portions of mixed-use structures in A Zones, lowest floors must be elevated to or above this flood protection elevation, meaning two feet above base flood elevation rather than just meeting the base flood elevation itself.

The same flood protection elevation standard extends to electrical, mechanical, and plumbing systems, which under § 238-8D(4) must generally sit at or above the elevation of the lowest floor required for the applicable zone, with the electric panel board required to sit at least three feet above the base flood elevation under § 238-8D(6). Note that § 238-8B(1)(f) uses a different, lower threshold for some elements: additions to structures or substantially improved structures need only reach one foot above base flood elevation for that specific driving-surface and addition standard, rather than the full two-foot freeboard applied to lowest floors.