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Radon Levels in Polk County, Tennessee

EPA puts Polk County in Zone 2, its middle radon zone, and only 3 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

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  • Share at 4+ pCi/L

    27.9%

    5.4 pts below TN

    Polk
    27.9%
    Tennessee
    33.3%

    43 tests, 2008 to 2017

  • Median result

    2.2pCi/L

    Below action level

    Polk
    2.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    43

    70th of 80 by tests

    Polk
    43
    Davidson
    5,592

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Tennessee

    43 of 80

    Middle half

    Polk
    27.9%
    Jefferson
    56.8%

    By share, of 80 with 30+ tests

Read a result for Polk County

Starts at Polk County's median, 2.2 pCi/L

2.2pCi/L

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

EPA’s reading of 2.2 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. Polk County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Polk County, At a glance

Polk County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Polk County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 71% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Polk County, 2023

Share of reported tests at or above 4 pCi/L, by year, Polk County
Share of reported tests at or above 4 pCi/L, by year, Polk County
YearShare of reported tests at or above 4 pCi/L
202218.2%
202366.7%

2023: 66.7%. Across these years the share ran from 18.2% to 66.7%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 3 tests were reported to CDC for Polk 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

Polk County, Compared

Polk County radon figures, compared

Calculated by Radon411

Polk County's 43 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.2 pCi/L and a maximum of 17.5 pCi/L, and 27.9% reached 4 pCi/L. Tennessee as a whole (95 Tennessee counties, pooled) comes to 33.3%: 5.4 points higher than here.

The newest figure, in 2023, counts only 3 tests (66.7% at or above 4 pCi/L), too few to compare, so this reading uses the 43-test figure.

Among its state's counties it ranks 43rd of 80 Tennessee counties with 30 or more tests for the same period. Statewide for the same period, Jefferson County reported the highest share (56.8%) and Chester County the lowest (0.0%).

Below the action level, 19 tests (44.2%) came in under 2 pCi/L, against 42.4% statewide, and 12 tests (27.9%) fell between 2 and 4, against 24.3% statewide. The busiest year on file was 2022, with 33 tests reported; the quietest, 2023, had 3.

EPA's 1993 zone map puts Polk County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 71% of the county's land moderate radon potential.

Next door, the shares run from 20.9% in Bradley County to 45.5% in Monroe County, with Bradley County below Polk County.

Polk County against Tennessee, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Polk County
Polk County4327.9%2.2 pCi/LThis county
Tennessee, pooled95 counties, pooled31,06633.3%Not pooled+5.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+7.8 points
Jefferson Countyhighest in the state14656.8%4.7 pCi/L+28.9 points
Chester Countylowest in the state440.0%1.1 pCi/L−27.9 points
Monroe County, TNborders it18945.5%3.5 pCi/L+17.6 points
Fannin County, GAborders it30044.7%3.5 pCi/L+16.8 points
Cherokee County, NCborders it1,04543.2%3.4 pCi/L+15.3 points
McMinn County, TNborders it10634.0%2.8 pCi/L+6.1 points
Murray County, GAborders it1323.1%1.3 pCi/L−4.8 points
Bradley County, TNborders it42520.9%1.9 pCi/L−7.0 points
Where Polk County's reported results fell, 2008 to 2017, laboratory, beside Tennessee and the United States
ResultPolk County testsPolk County shareTennessee shareU.S. shareAgainst Tennessee
Under 2 pCi/L1944.2%42.4%39.6%+1.8 points
2 to 4 pCi/L1227.9%24.3%24.7%+3.6 points
4 pCi/L and above1227.9%33.3%35.7%−5.4 points
Polk 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
Benton County38 of 803033.3%2.0 pCi/L
Perry County39 of 804032.5%2.0 pCi/L
DeKalb County40 of 805930.5%3.1 pCi/L
Robertson County41 of 8027328.9%1.9 pCi/L
Marion County42 of 807428.4%1.6 pCi/L
Polk County43 of 804327.9%2.2 pCi/L
Trousdale County44 of 803327.3%1.8 pCi/L
Rhea County45 of 804526.7%2.4 pCi/L
Dickson County46 of 8020926.3%2.1 pCi/L
Stewart County46 of 809526.3%2.1 pCi/L
Sumner County48 of 801,31126.0%1.9 pCi/L
Polk County radon tests by year, against Tennessee's pooled share
YearTestsAt or above 4 pCi/LMedianHighestTennessee, pooledChange from the row before
2023366.7%4.4 pCi/L4.5 pCi/L24.9%+48.5 points
20223318.2%2.6 pCi/L72.2 pCi/L23.8%First on file

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

Polk County, Geology

The ground under Polk County

Predicted

USGS's geologic map splits Polk County: 71.0% of its land is moderate radon potential and 28.9% high and 0.1% low. The map puts 70.6% of Polk County in the area it calls Unaka Mountains and 28.9% in Ridge and Valley. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 14, in the high band (12 to 17).

USGS's geologic areas under Polk County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Unaka MountainsPrecambrian and Paleozoic siltstone, sandstone, conglomerate, quartzite, phyllite, gneiss, granite, and metamorphosed volcanic rock.Moderate1170.6%
Ridge and ValleyPaleozoic sandstone and cherty dolostone.High1428.9%

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

Polk County beside the ground around it

Tennessee as a whole has more high-potential ground than Polk County: 47.2% of its land, against 28.9% here. Of the 6 counties that border it, 3 have more high-potential ground, McMinn County the most at 100%.

Share of land by USGS radon potential: Polk County, the 6 counties bordering it and Tennessee
AreaEPA zoneLow potentialModerate potentialHigh potential
Polk CountyZone 20.1%71.0%28.9%
Bradley CountyZone 10.3%None99.7%
McMinn CountyZone 1NoneNone100%
Cherokee County, NCZone 1None100%None
Murray County, GAZone 366.9%33.1%None
Monroe CountyZone 1None50.0%50.0%
Fannin County, GAZone 2None100%None
Tennessee95 counties, pooled by land areaVaries30.5%22.3%47.2%

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

Local help

Polk County, Local resources

Radon testing and mitigation in Polk County

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

What it means

Polk County, Questions

Questions about radon in Polk County

Are radon levels high in Polk County?

In 2023, 66.7% of the radon tests reported to CDC for Polk County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.4 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 42 reported a higher share; pooled, the state comes to 33.3%.

Which counties border Polk County?

Polk County borders 6 counties: Bradley County, TN, McMinn County, TN, Cherokee County, NC, Murray County, GA, Monroe County, TN and Fannin County, GA.

Products

Polk County, Products

Testing a home in Polk County

In Polk County, 27.9% of 43 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Polk County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Polk County homes, compared

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Polk County, Bordering counties

Counties bordering Polk County

Calculated by Radon411

Polk County, Cities and towns

Cities and towns in Polk County

Polk County is growing: the Census Bureau puts it at 18,592 residents on July 1, 2025, up 5.9% from 17,558 in 2020. That works out to 43 people per square mile of land. No town dominates: Benton, the largest, has 1,476 residents, 7.9% of the total. Together its 3 incorporated places hold 12.8% of those residents; the other 87.2% live outside any of them. Reported testing is thin here: 43 tests over 2008 to 2017, or 2.3 for every 1,000 residents (2025 estimate), where Tennessee as a whole comes to 4.2.

From Benton to Ducktown, CDC publishes no figure by town: each reads Polk County's.

The cities and towns in Polk County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Benton1,476−2.8%7.9%
Copperhill458+5.5%2.5%
Ducktown441−3.9%2.4%

3 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).

Polk County, Homes

Homes in Polk County

Of Polk County's 8,856 homes, 69% are detached houses, against 68% across Tennessee; 26% are mobile homes. Half of its homes were built before 1991, close to Tennessee's 1986: 15% date from before 1960 and 29% from 2000 or later. Owners live in 84% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.

Homes in Polk County, Tennessee, 2019 to 2023
HomesPolk CountyTennessee
Housing units8,8563,095,472
Detached houses69%68%
In buildings of 5 or more3%14%
Mobile homes26%8%
Built before 196015%18%
Built since 200029%29%
Middle year built19911986
Owner-occupied84%67%

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