Tennessee radon zones by county
All 95 Tennessee counties with their EPA radon zone: 39 are Zone 1 (highest), 32 are Zone 2 (moderate) and 24 are Zone 3 (low). Search, filter, and remember: a zone is a county average, not a verdict on your home.
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Which Tennessee counties have the highest radon?
EPA rates 39 of Tennessee's 95 counties Zone 1, the highest radon potential, with a predicted average indoor level above 4 pCi/L. 32 are Zone 2 and 24 are Zone 3. Zones are county averages, though: Tennessee's radon program has found action-level homes in every county, so test every home.
Test regardless of zone. EPA says its map "should not be used to determine if individual homes need to be tested" and that all homes should be tested. Tennessee's radon program has found action-level radon in every county. (EPA, TDEC)
Showing 95 of 95 counties.
| County | EPA zone | What the zone means |
|---|---|---|
| Anderson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Bedford County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Benton County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Bledsoe County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Blount County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Bradley County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Campbell County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Cannon County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Carroll County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Carter County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Cheatham County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Chester County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Claiborne County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Clay County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Cocke County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Coffee County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Crockett County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Cumberland County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Davidson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| DeKalb County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Decatur County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Dickson County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Dyer County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Fayette County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Fentress County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Franklin County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Gibson County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Giles County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Grainger County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Greene County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Grundy County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Hamblen County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Hamilton County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Hancock County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Hardeman County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Hardin County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Hawkins County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Haywood County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Henderson County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Henry County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Hickman County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Houston County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Humphreys County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Jackson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Jefferson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Johnson County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Knox County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Lake County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Lauderdale County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Lawrence County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Lewis County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Lincoln County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Loudon County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Macon County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Madison County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Marion County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Marshall County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Maury County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| McMinn County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| McNairy County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Meigs County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Monroe County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Montgomery County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Moore County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Morgan County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Obion County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Overton County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Perry County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Pickett County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Polk County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Putnam County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Rhea County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Roane County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Robertson County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Rutherford County County guide → | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Scott County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Sequatchie County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Sevier County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Shelby County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Smith County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Stewart County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Sullivan County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Sumner County County guide → | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Tipton County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| Trousdale County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Unicoi County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Union County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Van Buren County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Warren County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Washington County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Wayne County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Weakley County | Zone 3 | Low potential · Predicted county average under 2 pCi/L |
| White County | Zone 2 | Moderate potential · Predicted county average 2–4 pCi/L |
| Williamson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
| Wilson County | Zone 1 | Highest potential · Predicted county average above 4 pCi/L |
What do the radon zones mean?
EPA built the Map of Radon Zones in 1993 from indoor radon measurements, geology, aerial radioactivity, soil data and foundation types.[EPA] Each county got one of three labels based on its predicted average indoor level:
- Zone 1: predicted average above 4 pCi/L (EPA's action level for fixing a home).
- Zone 2: predicted average between 2 and 4 pCi/L.
- Zone 3: predicted average below 2 pCi/L.
Averages hide a lot. The U.S. Geological Survey report behind the map notes that very high indoor levels are possible on certain soils, such as those formed on the Chattanooga Shale, phosphate-rich soils or karst.[USGS] That's why a Zone 3 address can still test high, and a Zone 1 address can test low.
What should I do after checking my county?
Get a test. Tennessee residents can order one free kit per household from the state radon program, or hire a certified tester. Our radon testing guide walks through it step by step, and the cost guide covers what a fix runs.
Related guides
Sources
- EPA radon zone data file (June 2024)
- EPA Tennessee radon zone map (PDF)
- USGS Open-File Report 93-292-D, Tennessee chapter (1993)
- U.S. EPA Map of Radon Zones
- TDEC Tennessee Radon Program
County list and zones come from EPA's June 2024 radon-zone data file, cross-checked against EPA's Tennessee zone map. Verified 2026-10-21.