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

Howard County's Building Code adds Section 3115, Floodplain, directly after the International Building Code's Section 3114, and Section 3115.3 sets the elevation standard for substantial improvements to existing nonconforming structures located within a designated floodplain. Section 3115.3.1 requires the lowest floor of a residential structure, basement included, to be elevated to at least 2 feet above the 100-year flood elevation, the county's freeboard margin above the base flood elevation used on FEMA's maps. Section 3115.3.2 gives nonresidential buildings an alternative: floodproof rather than elevate, provided any part of the building below that same 2-foot mark is watertight, with walls substantially impermeable to water and structural components able to withstand the hydrostatic, hydrodynamic, and, where relevant, hurricane and tidal-wave loads described in the Army Corps of Engineers' floodproofing standard and Section 16.705(c) of the County Code.

The Building Code treats new construction in a designated floodplain more strictly than substantial improvements: Section 3115.2.1 bars new residential or nonresidential construction from occurring within a designated floodplain at all, with narrow exceptions for a destroyed nonconforming structure rebuilt on the same footprint within 12 months, and for transportation, utility, and open-deck improvements approved by the Department of Public Works. Adjacent to, rather than within, a designated floodplain, Section 3115.5 applies the same 2-foot freeboard or floodproofing standard.

Elevation compliance is not optional paperwork. The floodproofing-by-elevation option requires the owner to submit a FEMA elevation certificate, Form 086-0-33, completed by a professional engineer or licensed Maryland land surveyor certifying the as-built lowest floor is elevated at least 2 feet above the 100-year floodplain elevation, filed before foundation approval by the Building Official.