Williamson County, TN Environmental Rules: Flood Zones (2026)

02(A) states plainly that the Article applies to all areas within the unincorporated area of Williamson County, Tennessee; Franklin, Brentwood, Spring Hill, Fairview and Nolensville administer their own separate floodplain rules inside city limits. 02(B) adopts by reference FEMA's Flood Insurance Study dated December 20, 2024, and dozens of listed Flood Insurance Rate Map panel numbers as the basis for identifying Areas of Special Flood Hazard, meaning the county has updated its regulatory maps well after the ordinance's 2012 adoption. 02(D) bars locating, extending, converting or structurally altering any land, structure or use without full compliance with the Article's terms.

03(A) and reviews applications that must show the proposed lowest floor elevation, any non-residential floodproofing certification from a Tennessee registered engineer or architect, and, after construction, a FEMA Finished Construction Elevation Certificate before a Certificate of Compliance or Occupancy issues. 02(E) applies the stricter of this Article or any conflicting regulatory instrument. 05, though variances are barred entirely within any designated regulatory floodway if they would raise flood levels, and the county must warn an applicant in writing that building below base flood level raises flood insurance premiums as high as $25 per $100 of coverage.