What has changed with radon rules in Tennessee?
This log lists changes that affect whether new Tennessee homes must be built radon-resistant, plus new data and updates to this site, newest first. Each entry links to the county guide with the full source.
| Date | What changed | Where |
|---|---|---|
| Oct. 22, 2026 | Added a guide to radon in well water. | Radon in well water |
| Oct. 13, 2026 | A motion to opt unincorporated Henderson County out of state residential inspections failed 9–5. The state's 2018 code, which doesn't include the radon appendix, applies. | Henderson County |
| Sept. 3, 2026 | Murfreesboro adopted the 2024 residential code (Ordinance 26-O-34) without the radon appendix. | Rutherford County |
| Aug. 10, 2026 | Unincorporated Clay County's opt-out from residential building codes took effect. | Clay County |
| June 1, 2026 | Spring Hill's 2024 residential code (Ordinance 26-07) took effect, with no appendices referenced, including radon. | Maury County |
| Apr. 15, 2026 | Smyrna's 2024 residential code took effect with only Appendix BF (patio covers), not the radon appendix. | Rutherford County |
| Nov. 18, 2025 | Mt. Pleasant adopted the 2024 residential code (Ordinance 2025-1136) without specifically referencing the radon appendix. | Maury County |
| Nov. 2025 | Columbia adopted the 2024 residential code with the radon appendix (Appendix BE). | Maury County |
| July 16, 2025 | Metro Nashville's BL2025-898 was approved, adopting the 2024 residential code with the radon appendix (Appendix BE). | Davidson County |
| Mar. 31, 2025 | DeKalb County adopted the 2018 residential code for unincorporated areas, with no radon appendix listed. | DeKalb County |
| Jan. 14, 2025 | The Tennessee Department of Health published its Tennessee Radon Testing dashboard with 2022–2023 county results. | Tennessee radon statistics |
| Jan. 1, 2025 | Knoxville's 2024 residential code took effect without the radon appendix the city had required since its 2012 code. Unincorporated Knox County still requires it. | Knox County |
How do we keep this current?
We recheck county building codes and state data regularly and add dated entries here when something changes. Know of a change we've missed? Email info@tennesseeradonauthority.com with a link to the ordinance or source.
Last reviewed October 22, 2026 by the Tennessee Radon Authority editorial team. How we research.