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

Chapter 86's flood hazard reduction division sets the technical floor for anything built in a mapped special flood hazard area once FEMA has assigned base flood elevation data (Sec. 86-37, Sec. 86-77(8) or Sec. 86-133(c)). General standards require all new construction and substantial improvements to be anchored against flotation and lateral movement, built with flood-damage-resistant materials, and designed so mechanical, electrical and plumbing equipment stays out of floodwaters (Sec. 86-131). The specific residential standard is blunt: the lowest floor, including a basement, of a new or substantially improved house must sit at or above the base flood elevation, certified by a registered professional engineer, architect or land surveyor (Sec.

86-132(1)). Nonresidential buildings get an alternative: floodproof the structure watertight below the base flood elevation, with a professional engineer certifying the design and a record of the specific floodproofed elevation kept by the floodplain administrator (Sec. 86-132(2)). Enclosed areas below the lowest floor used only for parking, building access or storage must have flood vents totaling at least one square inch of net opening per square foot of enclosed area, with the bottom of each opening no higher than one foot above grade (Sec. 86-132(3)).

Manufactured homes and recreational vehicles carry their own anchoring and elevation rules (Sec. 86-132(4)-(5)). In the shallower AO/AH flood zones, the elevation floor is instead the depth number printed on the FIRM, or at least two feet above the highest adjacent grade if no depth is shown (Sec. 86-134).