Tennessee Radon Authority
Updated October 17, 2026
Tennessee radon guide › East Tennessee › Rhea County

Rhea County radon

Low-potential Zone 3 does not mean no risk. No local code requires radon-resistant construction, county-level test figures remain unverified, and certified testers are based outside the county.

Research reviewed October 16, 2026 · Sources linked throughout

Radon in Rhea County, Tennessee: quick answers

EPA zone: Zone 3Region: East TennesseeState test data: State test figures couldn't be confirmed, so they aren't shown

Is radon a problem in Rhea County, Tennessee?

It can be. Rhea County is in EPA Zone 3, the lowest predicted radon-potential category (below 2 pCi/L on average). Homes with high radon are still found in Zone 3, and the Tennessee Radon Program has found homes needing action in every Tennessee county, so test to know your home's level.

Do new homes in Rhea County, TN have to be built radon-resistant?

No. Spring City's 2018 code names no radon appendix, Graysville follows the state code without it, and Dayton's current code couldn't be confirmed. Local code details

How do I test my home for radon in Rhea County?

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

What radon level means I should fix my 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

Who can test or fix radon in Rhea County?

Tennessee doesn't license radon professionals, so look for NRPP or NRSB certification. Search both national directories by ZIP code; certified professionals often serve Rhea County from nearby cities. How to choose a radon professional

The bottom line

Test the house—not the map.

Rhea County sits in EPA Radon Zone 3, the agency’s lowest predicted-potential category. Yet the county borders higher-zone areas, its residential codes do not require radon-resistant construction, and the Tennessee dashboard did not yield a confirmed Rhea-specific reading. A zone is a planning signal, not a result for an individual home.

3EPA radon zone
0local certified measurement pros listed
0jurisdictions with a confirmed radon appendix
01 · RISK PROFILE

Zone 3, ringed by higher-potential counties

EPA Zone 3 denotes a predicted average indoor screening level below 2 pCi/L. It describes broad geology; it cannot tell you what is happening beneath a particular slab, basement, or crawlspace.

3Low potential
<2 pCi/L predicted average

Rhea’s designation is supported by two agreeing sources. The county’s location between Zone 1 and Zone 2 neighbors is a useful reminder that administrative boundaries do not stop soil gas.

County dashboard figures withheld. Three attempts to read the state map landed on neighboring Monroe County. The pre/post charts also resolve to East Region totals, not county counts. No Rhea number is published here without a tooltip explicitly naming Rhea.
02 · BUILDING CODES

Four jurisdictions, no confirmed radon mandate

Enforcement is split among city, county, and state officials. The code trail differs by place, but every verified path ends with radon-resistant construction optional rather than required.

Locally enforced

Spring City

The municipal code adopts the 2018 IRC and excepts sprinkler provisions R313.1 and R313.2. Title 12 names no IRC radon appendix.

Ord. #2021-09; later Appendix Q addition under Ord. #2022-06. Read Spring City Title 12
Current edition unresolved

Dayton

The last verifiable Title 12 snapshot adopted the 2012 IRC and no radon appendix. That copy dates to 2016; Dayton’s current residential code edition could not be confirmed.

Do not treat the 2012 edition as current without the latest Title 12. View the archived Title 12
State Fire Marshal

Graysville

Graysville appears on the state residential-permit list. The statewide residential standard is the 2018 IRC plus Appendix Q—not the radon appendix.

Radon-resistant construction is optional under the verified state standard. Check the SFMO jurisdiction list
Locally enforced · edition unresolved

Unincorporated Rhea

The county is absent from the state permit-required county list and staffs its own building inspector. Its code edition and adopting instrument are not published online.

A county call is still needed before naming an edition or appendix list. Rhea County official site
Practical conclusion

No Rhea County jurisdiction has a verified adoption of the IRC radon appendix. A new home can pass local code without radon-resistant features, so “new construction” is not a substitute for a test.

How do I find a certified radon professional in Rhea 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.

Search NRPPSearch NRSB

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.

03 · HOMEBUYERS

What to ask before closing

Tennessee’s standard seller disclosure names radon, but only asks what the seller knows. It does not guarantee that a home has been tested.

01

Ask for the report

Request the date, method, location, and complete result—not a verbal “it was fine.”

02

Keep a test contingency

Use the inspection window to obtain your own result rather than relying on the county’s zone.

03

Test new construction too

No verified local code requires radon-resistant features in a Rhea County new build.

04

Check the lowest lived-in level

Basements, slab-on-grade homes, and crawlspace homes can each have house-specific entry paths.

34,8442025 population estimate
+4.8%population change since 2020 estimate base
151building permits in 2025
15,955housing units, July 2025
04 · SOURCES

Primary records and live directories

Code status, risk context, market counts, and housing figures were reviewed against the linked sources. Access notes reflect the October 16, 2026 research pass.

  1. Spring City Municipal Code, Title 12
  2. Dayton Municipal Code, Title 12 — 2016 snapshot
  3. Tennessee State Fire Marshal residential permit list
  4. Tennessee Rule 0780-02-23
  5. Rhea County official site
  6. Tennessee Radon Testing dashboard
  7. Rhea County EPA zone profile
  8. EPA Map of Radon Zones: Tennessee
  9. NRPP professional search for 37321
  10. NRSB professional directory
  11. TN REALTORS Residential Property Condition Disclosure
  12. U.S. Census QuickFacts — Rhea County

Hero photograph source: Visit Rhea. This guide distinguishes verified code text from unresolved current records and does not substitute health-region totals for county-level measurements.