Knoxville, TN Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Standard freeboard
- 1 foot above base flood elevation
- TVA dam-controlled rivers
- 3 feet above base flood elevation
- Rivers covered
- Tennessee, French Broad, Holston
- Applies to
- New construction and substantial improvements
Summary
Knoxville requires new and substantially improved buildings in mapped flood zones to elevate the lowest floor at least one foot above base flood elevation, or three feet along TVA dam-controlled rivers.
new construction or substantial improvement of any residential building (or manufactured home) shall have all utilities (including electrical (utility meters not included), heating, ductwork, ventilating, plumbing, and air conditioning equipment) and the lowest floor, including basement, elevated to no lower than one (1) foot above the base flood elevation. Along any TVA dam-controlled river (Tennessee, French Broad, Holston), new construction and/or substantial improvement of any commercial, industrial, or nonresidential building in AE and/or shaded X zones when base flood elevation data is available, shall have all utilities (including electrical (utility meters not included), heating, ductwork, ventilating, plumbing, and air conditioning equipment) and the lowest floor, including basement, elevated to no lower than three (3) feet above the one (1) percent annual chance flood. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls and to ensure the unimpeded movement of floodwaters shall be provided in accordance with standards of article III, section 12-52(3).
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 80).
Full Breakdown
In AE and shaded X zones with base flood elevation data available, new construction or substantial improvement of a residential building or manufactured home must elevate the lowest floor and all utilities to at least one foot above base flood elevation. Along the Tennessee, French Broad, or Holston rivers -- all TVA dam-controlled -- that freeboard rises to three feet above the one percent annual chance flood, applying to commercial, industrial, and nonresidential buildings as well. Foundation walls used to raise a structure need openings that let floodwaters equalize on both sides. Freeboard is defined in § 12-3 as the safety margin above calculated flood levels that accounts for wave action and other unknowns.
Violations & Fines
Building below the required freeboard elevation in a mapped flood zone is a code violation; a structure lacking the required elevation certificate is presumed noncompliant until documentation proves otherwise.
Frequently Asked Questions
How high above flood level must a Knoxville home be built?
What counts as freeboard in Knoxville's flood code?
Sources & Official References
Other rules in Knoxville
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