Skip to content
RADON411

Locations and reports

Radon Levels in Greene County, Tennessee

EPA puts Greene County in Zone 1, its highest radon zone, and only 17 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    46.0%

    12.7 pts above TN

    Greene
    46.0%
    Tennessee
    33.3%

    385 tests, 2008 to 2017

  • Median result

    3.6pCi/L

    Below action level

    Greene
    3.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    385

    15th of 80 by tests

    Greene
    385
    Davidson
    5,592

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Tennessee

    14 of 80

    Top quarter

    Greene
    46.0%
    Jefferson
    56.8%

    By share, of 80 with 30+ tests

Read a result for Greene County

Starts at Greene County's median, 3.6 pCi/L

3.6pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 3.6 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Greene County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Greene County, At a glance

Greene County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Greene County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 95% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Greene County, 2023

Share of reported tests at or above 4 pCi/L, by year, Greene County
Share of reported tests at or above 4 pCi/L, by year, Greene County
YearShare of reported tests at or above 4 pCi/L
202219.1%
202347.1%

2023: 47.1%. Across these years the share ran from 19.1% to 47.1%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 17 tests were reported to CDC for Greene County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.

Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Greene County, Compared

Greene County radon figures, compared

Calculated by Radon411

In Greene County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (177 of 385) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 10.3 points higher. Across 95 Tennessee counties pooled together, 33.3% of tests reached that level, so Greene County runs 12.7 points above its state.

The newest figure, in 2023, counts only 17 tests (47.1% at or above 4 pCi/L), too few to compare, so this reading uses the 385-test figure.

Of 6 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 16.7% (Madison County, NC) to 49.6% (Washington County). By share, Greene County is 14th of 80 Tennessee counties with 30 or more tests for the same period.

Half the tests came in under 3.6 pCi/L and half over it; the single highest reached 121.3 pCi/L. Below the action level, 111 tests (28.8%) came in under 2 pCi/L, against 42.4% statewide, and 97 tests (25.2%) fell between 2 and 4, against 24.3% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 46.0% share point the same way here. USGS geology rates 95% of the county's land high radon potential. CDC also counts 9 tests taken after mitigation in Greene County for the same period: tests in homes where a fix was already in.

The busiest year on file was 2022, with 141 tests reported; the quietest, 2023, had 17.

Greene County against Tennessee, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Greene County
Greene County38546.0%3.6 pCi/LThis county
Tennessee, pooled95 counties, pooled31,06633.3%Not pooled−12.7 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−10.3 points
Jefferson Countyhighest in the state14656.8%4.7 pCi/L+10.8 points
Chester Countylowest in the state440.0%1.1 pCi/L−46.0 points
Washington County, TNborders it1,59049.6%3.9 pCi/L+3.6 points
Cocke County, TNborders it5646.4%3.8 pCi/L+0.4 points
Hamblen County, TNborders it18645.2%3.5 pCi/L−0.8 points
Hawkins County, TNborders it28938.4%2.7 pCi/L−7.6 points
Unicoi County, TNborders it13237.1%2.8 pCi/L−8.9 points
Madison County, NCborders it22816.7%1.3 pCi/L−29.3 points
Where Greene County's reported results fell, 2008 to 2017, laboratory, beside Tennessee and the United States
ResultGreene County testsGreene County shareTennessee shareU.S. shareAgainst Tennessee
Under 2 pCi/L11128.8%42.4%39.6%−13.6 points
2 to 4 pCi/L9725.2%24.3%24.7%+0.9 points
4 pCi/L and above17746.0%33.3%35.7%+12.7 points
Greene County ranked among the 80 Tennessee counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Grainger County9 of 805648.2%3.8 pCi/L
Carter County10 of 8034547.2%3.7 pCi/L
Jackson County11 of 804946.9%3.9 pCi/L
Pickett County12 of 804346.5%3.5 pCi/L
Cocke County13 of 805646.4%3.8 pCi/L
Greene County14 of 8038546.0%3.6 pCi/L
Monroe County15 of 8018945.5%3.5 pCi/L
Smith County16 of 805545.5%3.1 pCi/L
Hamblen County17 of 8018645.2%3.5 pCi/L
Claiborne County18 of 8012544.0%3.3 pCi/L
Blount County19 of 8074542.8%3.4 pCi/L
Greene County radon tests by year, against Tennessee's pooled share
YearTestsAt or above 4 pCi/LMedianHighestTennessee, pooledChange from the row before
20231747.1%2.9 pCi/L7.9 pCi/L24.9%+28.0 points
202214119.1%1.7 pCi/L14.9 pCi/L23.8%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Greene County, Geology

The ground under Greene County

Predicted

Most of the ground under Greene County is one class on USGS's geologic map: 94.5% of its land is high radon potential, with 5.5% moderate. The map puts 94.5% of Greene County in the area it calls Ridge and Valley and 5.3% in Unaka Mountains. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Greene County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Ridge and ValleyPaleozoic sandstone and cherty dolostone.High1494.5%
Unaka MountainsPrecambrian and Paleozoic siltstone, sandstone, conglomerate, quartzite, phyllite, gneiss, granite, and metamorphosed volcanic rock.Moderate115.3%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Greene County beside the ground around it

Greene County has more high-potential ground than Tennessee as a whole: 94.5% of its land against 47.2%. Of the 6 counties that border it, 3 have more high-potential ground, Hamblen County the most at 100%.

Share of land by USGS radon potential: Greene County, the 6 counties bordering it and Tennessee
AreaEPA zoneLow potentialModerate potentialHigh potential
Greene CountyZone 1None5.5%94.5%
Hawkins CountyZone 1NoneNone100%
Cocke CountyZone 2None32.9%67.1%
Hamblen CountyZone 1NoneNone100%
Unicoi CountyZone 2None35.6%64.5%
Madison County, NCZone 2None99.9%0.1%
Washington CountyZone 1NoneNone100%
Tennessee95 counties, pooled by land areaVaries30.5%22.3%47.2%

The map rates the ground, not the air in any home.

Local help

Greene County, Local resources

Radon testing and mitigation in Greene County

What Tennessee's program says
Phone
1-800-232-1139
Email
TDEC.Radon@tn.gov

What it means

Greene County, Questions

Questions about radon in Greene County

Are radon levels high in Greene County?

In 2023, 47.1% of the radon tests reported to CDC for Greene County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.9 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 33.3%.

Which counties border Greene County?

Greene County borders 6 counties: Hawkins County, TN, Cocke County, TN, Hamblen County, TN, Unicoi County, TN, Madison County, NC and Washington County, TN.

Products

Greene County, Products

Testing a home in Greene County

In Greene County, 46.0% of 385 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 1 the year-round level in Greene County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Greene County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Greene County

Explore

Greene County, Bordering counties

Counties bordering Greene County

Calculated by Radon411

Greene County, Cities and towns

Cities and towns in Greene County

The Census Bureau estimates 73,831 residents in Greene County for July 1, 2025, 3,492 more than in 2020 (+5.0%). That works out to 119 people per square mile of land. Its largest town, Greeneville, has 16,141 residents, 21.9% of the total. Together its 4 incorporated places hold 30.6% of those residents; the other 69.4% live outside any of them. CDC's 385 reported tests for 2008 to 2017 work out to 5.2 per 1,000 residents (2025 estimate), close to Tennessee's 4.2.

From Greeneville to Baileyton, CDC publishes no figure by town: each reads Greene County's.

The cities and towns in Greene County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Greeneville16,141+4.0%21.9%
Tusculum3,421+3.9%4.6%
Mosheim2,547+2.7%3.4%
Baileyton464+6.4%0.6%

4 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Greene County, Homes

Homes in Greene County

Of Greene County's 32,470 homes, 67% are detached houses, against 68% across Tennessee; 24% are mobile homes. Half of its homes were built before 1983, close to Tennessee's 1986: 20% date from before 1960 and 23% from 2000 or later. Owners live in 76% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.

Homes in Greene County, Tennessee, 2019 to 2023
HomesGreene CountyTennessee
Housing units32,4703,095,472
Detached houses67%68%
In buildings of 5 or more5%14%
Mobile homes24%8%
Built before 196020%18%
Built since 200023%29%
Middle year built19831986
Owner-occupied76%67%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.