Travis County, TX Environmental Rules: Flood Elevation Requirements (2026)

Travis County Code Sec. 2 percent annual chance floodplain outside the Colorado River Corridor, two feet above the 1 percent annual chance floodplain inside the Corridor, or two feet above the 1 percent annual chance floodplain calculated using Atlas 14 data. Sec. 122 applies that two-foot freeboard to actual construction. 2 percent floodplain, within 100 feet of a Zone A, or within Zones A, A1-30, AE or AH must have the lowest floor, including any basement, and all utilities elevated to or above that minimum flood protection elevation.

In an AO Zone, the lowest floor and utilities must sit at least three feet above the depth number printed on the FIRM, or three feet above the highest adjacent grade if no depth number is shown. Nonresidential structures face the same elevation floor but may instead be completely floodproofed to that height with watertight walls and structural components able to resist hydrostatic and hydrodynamic loads, a design a Texas-licensed engineer or architect must certify to the Floodplain Administrator. Fully enclosed areas below the lowest floor used only for parking, access or storage must have flood vents: a minimum of two openings totaling at least one square inch per square foot of enclosed area, with the tops no higher than one foot above grade or the base flood elevation.

2 percent annual chance flood rather than the ordinary base flood. New construction may not raise the water-surface elevation of the floodplain on adjacent or county property without a FEMA-approved Conditional Letter of Map Revision.