Irving, TX Environmental Rules: Flood Elevation Requirements (2026)

Section 47-14 of the Flood Damage Prevention chapter sets Irving's specific construction standards for property within a mapped special flood hazard area. For new residential construction, the lowest floor, including any basement, must be elevated to at least two feet above the base flood elevation shown on the FIRM, and a registered professional engineer must certify to the Director of Public Works that the standard is met. Once that two-foot freeboard is achieved, the floor slab elevation of the new residential structure cannot be set lower than the top of the street curb on the street it fronts.

Nonresidential buildings have a second compliance path: they can either elevate the lowest floor two feet above base flood level the same as residential structures, or be designed and floodproofed watertight below that level, with walls substantially impermeable to water and structural components able to resist hydrostatic and hydrodynamic loads; a professional engineer or architect must certify the floodproofing design and record the specific elevation to which the structure is floodproofed. Manufactured homes placed less than two feet above base flood level must be anchored to resist flotation, collapse, or lateral movement, using methods such as over-the-top or frame ties to ground anchors, and no manufactured home may be sited in a designated floodway.

Section 47-11(2)(k) reinforces the elevation floor at the permitting stage: no development permit for new construction or substantial improvement in a special flood hazard area can issue unless the lowest floor slab elevation is at least two feet above the base flood level, and once that threshold is met the city cannot demand additional floodproofing beyond what Section 47-14 already requires.