Marshall County, Tennessee · researched Oct. 14, 2026
Marshall County Radon
Every Marshall County jurisdiction is on the 2018 residential code, yet none has adopted its radon appendix. In a fast-growing county with almost no local test data, the safest conclusion is simple: test the house, not the county average.
EPA zone: Zone 1Region: Middle TennesseeState test data: State test figures confirmed on repeat checks
Yes, it can be. Marshall County is in EPA Zone 1, the highest radon-potential category, where the predicted average indoor screening level is above 4 pCi/L. Levels vary from house to house, so a test is the only way to know your home's level.
No. Unincorporated Marshall County, Lewisburg, Chapel Hill and Cornersville all adopt the 2018 code without the radon appendix. Local code details
Order a free short-term kit from the Tennessee Radon Program online or by calling 1-800-232-1139. Place it on the lowest lived-in floor, about 3 feet off the floor, for 3 to 5 days, then mail it back right away. How to test your home
EPA recommends fixing your home if radon is 4 pCi/L or higher, and considering a fix between 2 and 4 pCi/L. Confirm a high short-term result with a second test first. What your result means
Tennessee doesn't license radon professionals, so look for NRPP or NRSB certification. Search both national directories by ZIP code; certified professionals often serve Marshall County from nearby cities. How to choose a radon professional
All four jurisdictions adopt the 2018 IRC without its optional radon appendix. That leaves radon-resistant new construction optional, even though Marshall County is mapped in EPA Zone 1.
No ordinance reviewed lists Appendix F, the 2018 IRC’s Radon Control Methods appendix. Local code therefore does not make radon-resistant construction mandatory.
The county’s adopted-codes page lists editions but no appendices. Confirm the underlying resolution with Building Codes & Zoning.
The MTAS code includes a rolling administrative-update clause. A newer edition could have been adopted by regulation; confirm the currently enforced edition with the building inspector.
Title 12 adopts the 2018 code family and modifies energy and sprinkler rules; it does not adopt the radon appendix.
Title 12 incorporates state residential standards and explicitly includes Appendix Q. Optional or recommended provisions are not construed as adopted.
The Tennessee dashboard’s Marshall County tooltip was live-checked on Oct. 14, 2026. Average, median, and maximum all display 0.9 pCi/L — but the workbook does not show a county test count.
Three identical values suggest one test or a very small sample, but the exact count cannot be confirmed because the dashboard does not expose it.
The accompanying pre- and post-mitigation band charts are labeled by health region. When Marshall County is selected, they show the South Central Region — not Marshall County alone.
Tennessee doesn't license radon testers or mitigators, so national certification is the best way to check qualifications. The Tennessee Radon Program points residents to two directories: search them by ZIP code and widen the radius if nothing is listed nearby.
We don't recommend or rank companies. Before you hire, check the certification number in the directory yourself and ask for a follow-up test after any system is installed. Questions to ask a radon professional.
Use these Tennessee and national resources to get a test, talk through a result, or find qualified help.
Hotline information: U.S. Environmental Protection Agency and Centers for Disease Control and Prevention.
Code records and live directory/dashboard checks were reviewed Oct. 14, 2026. Links below lead to the source sites used for the claims above.