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Radon Levels in Shelby County, Alabama

EPA puts Shelby County in Zone 2, its middle radon zone, and most reported tests there come back low, though 11.3% of 373 (2008 to 2017, laboratory totals) reached 4 pCi/L. 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

    11.3%

    10.6 pts below AL

    Shelby
    11.3%
    Alabama
    21.9%

    373 tests, 2008 to 2017

  • Median result

    1.3pCi/L

    Below action level

    Shelby
    1.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    373

    7th of 27 by tests

    Shelby
    373
    Madison
    5,178

    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 Alabama

    21 of 27

    Lowest quarter

    Shelby
    11.3%
    Colbert
    36.2%

    By share, of 27 with 30+ tests

Read a result for Shelby County

Starts at Shelby County's median, 1.3 pCi/L

1.3pCi/L

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

EPA’s reading of 1.3 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Shelby County's median reported result, 2008 to 2017.

Interpret this reading

The data

Shelby County, At a glance

Shelby County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Shelby 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 92% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Shelby County, 2008 to 2017, laboratory

Reported results by concentration band, Shelby County, 2008 to 2017, laboratory
Under 2 pCi/L: 70%2 to 4 pCi/L: 19%4 pCi/L and above: 11%

Of 373 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Shelby County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L25969.4%
2 to 4 pCi/L7219.3%
4 pCi/L and above4211.3%
What these figures count

These are the 373 tests reported to CDC for Shelby County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Shelby County, Compared

Shelby County radon figures, compared

Calculated by Radon411

Shelby County reports fewer high tests than Alabama overall. 11.3% of its 373 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 10.6 points below the 21.9% pooled from 65 Alabama counties.

Ordered from highest share down, it comes 21st of 27 Alabama counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Shelby County sits 24.4 points below it.

Next door, the shares run from 10.7% in Jefferson County to 18.5% in Talladega County, with Jefferson County below Shelby County. Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 11.3% share point the same way here.

Half the tests came in under 1.3 pCi/L and half over it; the single highest reached 14.6 pCi/L. The rest split 69.4% under 2 pCi/L and 19.3% from 2 to 4 (Alabama: 54.3% and 23.8%).

CDC's ten-year totals for Shelby County went from 394 tests (2005 to 2014) to 373 (2008 to 2017), the share going from 11.4% to 11.3%.

Shelby County against Alabama, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Shelby County
Shelby County37311.3%1.3 pCi/LThis county
Alabama, pooled65 counties, pooled12,56921.9%Not pooled+10.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+24.4 points
Colbert Countyhighest in the state87136.2%2.7 pCi/L+24.9 points
Baldwin Countylowest in the state310.0%1.0 pCi/L−11.3 points
Bibb County, ALborders it425.0%2.5 pCi/L+13.7 points
Talladega County, ALborders it12418.5%1.6 pCi/L+7.2 points
St. Clair County, ALborders it9314.0%1.2 pCi/L+2.7 points
Chilton County, ALborders it1811.1%1.1 pCi/L−0.2 points
Jefferson County, ALborders it91210.7%1.2 pCi/L−0.6 points
Coosa County, ALborders it90.0%1.4 pCi/L−11.3 points
Where Shelby County's reported results fell, 2008 to 2017, laboratory, beside Alabama and the United States
ResultShelby County testsShelby County shareAlabama shareU.S. shareAgainst Alabama
Under 2 pCi/L25969.4%54.3%39.6%+15.1 points
2 to 4 pCi/L7219.3%23.8%24.7%−4.5 points
4 pCi/L and above4211.3%21.9%35.7%−10.6 points
Shelby County ranked among the 27 Alabama counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
St. Clair County16 of 279314.0%1.2 pCi/L
Blount County17 of 274413.6%2.0 pCi/L
DeKalb County18 of 276813.2%0.9 pCi/L
Lee County19 of 278112.3%1.3 pCi/L
Cullman County20 of 277911.4%1.5 pCi/L
Shelby County21 of 2737311.3%1.3 pCi/L
Jefferson County22 of 2791210.7%1.2 pCi/L
Limestone County23 of 2767410.1%1.3 pCi/L
Montgomery County24 of 271039.7%0.9 pCi/L
Tuscaloosa County25 of 27828.5%1.4 pCi/L
Mobile County26 of 27523.8%0.5 pCi/L
Shelby County ten-year laboratory totals, against Alabama's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestAlabama, pooledChange from the row before
2008 to 201737311.3%1.3 pCi/L14.6 pCi/L21.9%+0.8 points
2007 to 201642010.5%1.3 pCi/L14.6 pCi/L22.0%+0.2 points
2006 to 201543610.3%1.3 pCi/L14.6 pCi/L22.0%−1.1 points
2005 to 201439411.4%1.4 pCi/L14.6 pCi/L22.4%First on file

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

Shelby County, Geology

The ground under Shelby County

Predicted

Most of the ground under Shelby County is one class on USGS's geologic map: 92.0% of its land is moderate radon potential, with 8.0% high. The map puts 92.0% of Shelby County in the area it calls Valley and Ridge and 8.0% in Northern Piedmont. USGS gives the first a radon index of 9, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Shelby County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Valley and RidgeChattanooga black shale, Cambrian-Ordovician limestone and sandstone.Moderate992.0%
Northern PiedmontSchist, metagraywake, phyllite, quartz diorite gneiss, amphibolite gneiss, quartz monzonite.High128.0%

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

Shelby County beside the ground around it

On high-potential ground Shelby County is close to Alabama as a whole: 8.0% of its land against 14.3%. Of the 6 counties that border it, 3 have more high-potential ground, Talladega County the most at 54.8%.

Share of land by USGS radon potential: Shelby County, the 6 counties bordering it and Alabama
AreaEPA zoneLow potentialModerate potentialHigh potential
Shelby CountyZone 2None92.0%8.0%
Jefferson CountyZone 2None100%None
Chilton CountyZone 2None63.3%36.7%
Bibb CountyZone 2None100%None
Talladega CountyZone 1None45.2%54.8%
St. Clair CountyZone 2None100%None
Coosa CountyZone 1None53.4%46.6%
Alabama67 counties, pooled by land areaVaries35.2%50.4%14.3%

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

Local help

Shelby County, Local resources

Radon testing and mitigation in Shelby County

What Alabama's program says
Phone
(334) 290-6244

What it means

Shelby County, Questions

Questions about radon in Shelby County

Are radon levels high in Shelby County?

Over the 2008 to 2017 laboratory totals, 11.3% of the radon tests reported to CDC for Shelby County, Alabama were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.3 pCi/L. Of 27 Alabama counties with 30 or more tests for the same period, 20 reported a higher share; pooled, the state comes to 21.9%.

Which counties border Shelby County?

Shelby County borders 6 counties: Jefferson County, Chilton County, Bibb County, Talladega County, St. Clair County and Coosa County.

Products

Shelby County, Products

Testing a home in Shelby County

In Shelby County, 11.3% of 373 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 21.9% pooled across Alabama. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Shelby County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Shelby County homes, compared

Explore

Shelby County, Bordering counties

Counties bordering Shelby County

Calculated by Radon411

Shelby County, Cities and towns

Cities and towns in Shelby County

Shelby County is growing: the Census Bureau puts it at 238,552 residents on July 1, 2025, up 6.5% from 223,898 in 2020. That works out to 304 people per square mile of land. Birmingham, the largest place on its list (195,893 residents in all), extends beyond Shelby County, so no share of the total is worked out for it. Reported testing is thin here: 373 tests over 2008 to 2017, or 1.6 for every 1,000 residents (2025 estimate), where Alabama as a whole comes to 2.4.

From Birmingham to Wilton, CDC publishes no figure by town: each reads Shelby County's.

The 12 largest cities and towns in Shelby County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Birminghamextends beyond Shelby County195,893−2.2%Counted whole
Hooverextends beyond Shelby County93,550+1.0%Counted whole
Vestavia Hillsextends beyond Shelby County38,306−2.3%Counted whole
Alabaster34,748+4.0%14.6%
Pelham25,664+5.9%10.8%
Helenaextends beyond Shelby County23,388+4.9%Counted whole
Caleraextends beyond Shelby County18,992+14.2%Counted whole
Chelsea17,716+16.2%7.4%
Leedsextends beyond Shelby County12,831+3.6%Counted whole
Montevallo7,872+9.0%3.3%
Columbiana5,106+12.5%2.1%
Indian Springs Village2,553+0.6%1.1%
  • Westover
  • Vincent (part)
  • Harpersville
  • Wilsonville
  • Wilton

17 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Shelby County is counted whole, so it has no share.

Shelby County, Homes

Homes in Shelby County

Shelby County is a place of houses on their own lots: 76% of its 90,805 homes are detached single-family houses, against 69% across Alabama. Much of Shelby County is recent building: 43% of its homes have gone up since 2000 and the middle year built is 1997, against 1985 for Alabama. Owners live in 81% of the occupied homes (Alabama: 70%), so for most households a test and a fix are their own to order.

Homes in Shelby County, Alabama, 2019 to 2023
HomesShelby CountyAlabama
Housing units90,8052,316,192
Detached houses76%69%
In buildings of 5 or more9%12%
Mobile homes8%13%
Built before 19604%16%
Built since 200043%27%
Middle year built19971985
Owner-occupied81%70%

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