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

Section 50-132 of the Wylie Code of Ordinances sets the specific flood-hazard-reduction standards that apply once base flood elevation data exists for a site under section 50-79, section 50-107(8) or section 50-133(c). For residential construction, the lowest floor, including any basement, must sit at least two feet above the base flood elevation, and a registered professional engineer or land surveyor must certify to the floodplain administrator that the structure meets the standard described in the section 50-108(a)(1) permit application. Nonresidential buildings get an alternative: they may either meet the same two-foot freeboard or be floodproofed below that level with watertight, substantially impermeable walls and structural components able to resist hydrostatic and hydrodynamic loads, certified by a registered engineer or architect.

Enclosed areas below the lowest floor used only for parking, building access or storage must have at least two flood openings on separate walls totaling one square inch of net area per square foot of enclosed space, with the bottom of each opening no higher than one foot above grade. Manufactured homes placed in mapped Zones A1-30, AH and AE outside an existing park must also be elevated so the lowest floor clears the base flood elevation by two feet and be anchored against flotation and lateral movement.

The city engineer or the city manager's designated representative administers these standards as floodplain administrator under section 50-106, and every application runs through the permit process in section 50-108.