F
Appendix on the books
McMinnville expressly includes 2018 IRC Appendix F; its local application is not yet confirmed.1
Jurisdiction by jurisdiction
The code line changes at the city limits.
Only McMinnville provides a clean, express listing of the radon appendix. Its local application is not yet confirmed; Morrison’s wording is broad but unclear, and the county and its smallest towns do not publish enough to reach a defensible answer.
McMinnville
ADOPTION CONFIRMED
2018 IRC + Appendix F. Municipal Code §12-801 lists Appendix F among the adopted appendices, as amended by Ordinance #1870 in December 2023. Whether and how the appendix applies to projects in this Zone 2 county—and how inspectors enforce it—was not verified.1
Morrison
AMBIGUOUS
2018 IRC. Ordinance 23-03 says the adopted codes and “any appendices” are incorporated, but gives no IRC appendix list. Whether officials treat Appendix F as adopted and enforceable is not confirmed.2
Unincorporated
NOT VERIFIED
The county says it enforces adopted “International Codes,” but does not name the edition online. Its IRC edition and radon-appendix status remain open.3
Viola
NOT VERIFIED
No published building code or local inspection program was found. If there is no local program, State Fire Marshal standards may apply—but that local status was not confirmed.4
Centertown
NOT VERIFIED
No published building code or local inspection program was found. Confirm with the town recorder or State Fire Marshal before stating which residential standard controls.4
Adopted does not answer every application question
Appendix F supplies radon-control construction methods for covered homes. The published code confirms McMinnville listed it, but the research did not verify its local Zone 2 application or how inspectors handle the rough-in. A post-construction radon test remains the property-level check.
Risk profile
Zone 2 is clear. The county readings are not.
EPA’s county map places Warren County in Zone 2, the moderate-potential band with a predicted average indoor level of 2–4 pCi/L.6 That designation cannot tell a buyer what one house will measure.
9.1
displayed average pCi/L
vs.
5.1
displayed maximum pCi/L
A maximum cannot be lower than its average.
The Tennessee Radon Testing dashboard showed these two values on a tooltip labeled “County: Warren” on October 15, 2026. The median did not render. Because the pair is mathematically impossible, none of Warren County’s tooltip figures should be published as fact.7
Do use
EPA Zone 2, with the explanation that it is a county-scale potential category and not a property result.
Do not use
The dashboard’s 9.1 average, 5.1 maximum, or earlier unverified 1.5 median as Warren County facts.
Important: the dashboard’s pre- and post-mitigation band charts are grouped by health region, not by selected county. They cannot support a Warren County test count or a county-level percentage above 4 pCi/L.7
How do I find a certified radon professional in Warren County?
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.
For a purchase contract
A Warren County buyer playbook.
01 · TEST
Test the house, not the zone.
Make radon part of the inspection contingency. Tennessee’s standard disclosure form has no dedicated radon question, though its instructions name radon among buyer inspection contingencies.10
02 · VERIFY
Ask what the permit required.
For a McMinnville new build, ask whether Appendix F applied to the permit, then request the rough-in and inspection record if it did. Do not assume the same code status outside the city.
03 · SCHEDULE
Leave room for travel.
No certified measurement provider was found based in the county. A contract window should account for a professional traveling from Sparta, Christiana, Murfreesboro, or farther out.89
04 · RETEST
Treat radon-ready as unmeasured.
A passive system or rough-in is a construction feature, not a measured result. Test after the home is complete and occupied under proper closed-house conditions.
Practical next steps
Radon testing resources
Test your home
- Get a free test kit from TDEC, Tennessee’s radon program.
- Buy a kit by phone: 1-800-SOS-RADON (1-800-767-7236).
- Get live help with your questions: 1-800-55RADON (1-800-557-2366).
- Find a certified pro: NRPP 800-269-4174 · NRSB 866-329-3474.
Hotline information · EPA and CDC
If your result comes back high
- 1-800-644-6999 — the Fix-It Hotline, for general guidance on lowering radon in your home.
Hotline information · EPA and CDC
Learn more
Why it matters
- Radon causes about 21,000 US lung cancer deaths a year — the second-leading cause overall and the leading cause among people who never smoked.
- Smoking plus radon raises the risk roughly ~9×.
- About 1 in 15 homes has high radon.
- Retest at least every 2 years if you have a mitigation system, and after renovations or changes to how you use the lowest floor. EPA recommends taking action at 4 pCi/L and considering it between 2 and 4 pCi/L.
Health statistics · American Lung Association
Beyond building code
No local radon rule surfaced.
The research found no Warren County, McMinnville, Morrison, Viola, or Centertown rule specific to radon in public buildings, schools, or real-estate transactions.
Schools
A national policy review classifies Tennessee’s school approach as “Encourage,” not mandate, with no specified retesting frequency or mitigation requirement.5
Real estate
No county-specific disclosure or test mandate was found. Tennessee’s condition disclosure form has no dedicated radon question and advises buyers to include radon among inspection contingencies.10
Source ledger
Primary links and verification trail.
- McMinnville Municipal Code, Title 12 — 2018 IRC and express appendix list; MTAS compilation.
- Morrison Ordinance 23-03 — 2018 code adoption and general appendix language.
- Warren County Building & Environmental Codes — department scope; no edition named.
- MTAS: 10 Simple Questions on Code Adoption — Tennessee state-code baseline and local-program context.
- Radon in Schools: state-law review — Tennessee listed as voluntary/encouraged.
- Archived EPA Tennessee radon-zone map — Warren County in Zone 2.
- Tennessee Radon Testing dashboard — Warren tooltip and health-region chart structure, live-checked October 15, 2026.
- NRPP professional directory — McMinnville-area search, live-checked October 15, 2026.
- NRSB Find a Professional — 25- and 100-mile searches, live-checked October 15, 2026.
- Tennessee Residential Property Condition Disclosure (RF201) — no dedicated radon question; inspection-contingency guidance.
- Homes.com: McMinnville new construction — listing snapshot cited in research.
- NewHomeSource: McMinnville communities — community snapshot cited in research.
- City of McMinnville July 2025 permits — includes new single-family dwellings.