EPA radon potential
Zone 3EPA’s low-potential category. The county designation was verified through a secondary county table that cites the EPA map; direct map corroboration remains open. [7]
01 / QUICK READ
The map looks reassuring. The local safeguards are thin.
Radon-resistant new construction is not mandatory in Trenton, Milan or Humboldt.
Trenton’s blanket 2018 IRC adoption textually includes Appendix F, but nothing makes its radon-control provisions mandatory. Milan omits Appendix F from its list; Humboldt’s published adoption names no appendices. [1] [2] [3]
Bottom line
Zone 3 is a lower-potential label, not a guarantee. Test existing homes and new builds.
Zone 3 is a lower-potential label, not a guarantee. Test existing homes and new builds.
Zone 3EPA low-potential designation, sourced from a county table that reproduces EPA mapping. [7]
0.9pCi/L dashboard average; indicative because no county sample size is shown. [8]
0NRPP-listed professionals based in Gibson County or nearby Madison County. [9]
73.5 miDistance to the nearest listed measurement professional, in Memphis, from the Trenton search. [9]
02 / RISK & DATA
Low observed readings, unknown sample size.
The dashboard numbers were county-labeled and repeated, but they are a limited public snapshot rather than a population estimate.
INDICATIVE · SAMPLE SIZE UNKNOWN
Tennessee Radon Testing dashboard
0.9Average · pCi/L
0.8Median · pCi/L
1.7Maximum · pCi/L
The tooltip’s own label confirmed “County: Gibson” across multiple loads. One complete tooltip showed all three values; additional checks confirmed the maximum. Because the figures rendered intermittently and the dashboard shows no test count, treat them as indicative—not statistically robust. [8]
The lower charts are not Gibson County totals.
The before- and after-mitigation charts aggregate by health region. Selecting Gibson narrows them to the West Region, not to Gibson County. No regional bar or percentage should be republished as a county statistic.
03 / BUILDING CODES
Three town codes, three versions of “optional.”
The unincorporated county runs its own building-inspector office, but its code edition and appendix list were not available online.
TEXTUALLY INCLUDED · NOT MANDATED
Trenton
Trenton adopted the 2018 IRC “including appendix chapters” through Ordinance #314 in May 2018. That blanket language includes Appendix F in the adopted text, but no local provision makes the radon-control methods mandatory. The practical result is optional construction. [1]
APPENDIX F OMITTED
Milan
Milan’s 2018 IRC adoption names Appendices A, B, C, G, H, J, M, N and P. Appendix F is absent, so radon-resistant construction is not mandatory. The history cites Ordinances #2018-4 and #2020-09. [2]
NO APPENDIX LIST
Humboldt
The published code adopts the 2006 IRC and names no appendices. Because IRC appendices apply only when specifically referenced, its radon appendix is not adopted. [3]
OPEN QUESTION
Unincorporated Gibson County
Gibson County is absent from the State Fire Marshal’s list of counties where a state residential permit is required. It operates its own Building Inspector office, so the county—not the state program—handles unincorporated residential enforcement. [4] [5]
No Gibson-specific radon rule was found.
No local mandate surfaced for public buildings, schools or real-estate transactions. Tennessee is classified as encouraging—not requiring—school radon testing. Absence from web sources is not definitive; a direct county or school-district confirmation would close the question. [11]
How do I find a certified radon professional in Gibson 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.
04 / HOMEBUYERS
New does not automatically mean radon-ready.
None of the three largest towns mandates radon-resistant construction, and the unincorporated county appendix status is unresolved. Ask the builder what was installed, then test the completed home.
Tennessee’s standard RF-201 disclosure form asks sellers about known environmental hazards including radon and advises buyers to include inspection contingencies. It does not replace an independent test. [10]
Transaction plan
- Put radon testing inside the inspection or due-diligence window.
- Use an independent, nationally certified measurement professional where available.
- For new construction, ask for any passive-system plans and installation photos.
- If mitigation is installed, retest to verify performance.
05 / TESTING RESOURCES
Use the directories—then verify the credential.
No listed professional is based nearby, so confirm service range, current certification and transaction timing before booking.
Start with the NRPP search
The Trenton search provides the clearest current view of listed measurement professionals and their distance from ZIP 38382.
Search NRPP near Trenton →Check NRSBThe October 2026 tool appeared to malfunction; verify again before drawing conclusionsView Tennessee’s dashboardUse county-labeled tooltips; lower charts are regionalRead EPA’s zone guidanceUnderstand what county zones can—and cannot—tell youReview Tennessee RF-201Statewide property-condition disclosure form
06 / FAQ
Questions Gibson County homeowners ask
Is Gibson County in a high-radon zone?
No. Gibson County is shown as EPA Zone 3, the low-potential category. That broad label cannot predict an individual home, so a test is still the property-level answer.
What does the Tennessee dashboard show for Gibson County?
County-labeled tooltip checks showed approximately 0.9 pCi/L average, 0.8 median and 1.7 maximum. Because values rendered intermittently and no sample size is published, treat them as indicative rather than statistically robust.
Does Trenton require radon-resistant new construction?
No. Trenton’s 2018 IRC adoption says it includes appendix chapters, so Appendix F is textually adopted, but the ordinance does not make its radon-control methods mandatory. The practical result is optional construction.
Do Milan or Humboldt adopt the radon appendix?
Milan’s enumerated 2018 IRC appendix list omits Appendix F. Humboldt’s published 2006 IRC adoption names no appendices, and its codification appears stale. Neither published code makes radon-resistant construction mandatory.
Are certified radon testers based in Gibson County?
The October 2026 NRPP search found none based in Gibson County or nearby Madison County. The nearest listed measurement professionals were in Memphis, more than 73 miles from Trenton. The NRSB tool malfunctioned, so no NRSB conclusion is made.
07 / SOURCES
Primary documents, public data & directories
- Trenton Municipal Code, Title 12 — 2018 IRC adoption and ordinance history.
- Milan Municipal Code, Title 12 — 2018 IRC and appendix list.
- Humboldt Municipal Code, Title 12 — published 2006 IRC adoption.
- Gibson County Building Inspector — office and contact information, checked October 16, 2026.
- Tennessee State Fire Marshal residential-permit jurisdictions.
- MTAS statewide building-standards reference.
- EPA Map of Radon Zones: Tennessee; see also the EPA zone-map page.
- Tennessee Radon Testing dashboard — live Gibson County tooltip checks, October 16, 2026.
- NRPP professional search near 38382 — live search, October 16, 2026.
- NRSB Find a Professional — tool returned implausible empty results.
- Tennessee REALTORS RF-201 — property-condition disclosure form, version 01/01/2025.
- Radon in Schools: review of state laws — Tennessee classified as “Encourage.”
- Tennessee HB1269 — proposed school radon-testing language; enactment was not verified.
- Census QuickFacts: Gibson County — population and housing context.
- FRED: Gibson County private housing permits — 2020–2025 annual series.
- World Population Review: Gibson County cities — municipal growth context.
Method note. This page separates verified ordinance findings from inference and open questions. Dashboard values are presented with the report’s rendering and sample-size caveats. Health-region bars are not presented as county statistics. Directory results are snapshots, not a census.