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Radon Levels in Jefferson County, Alabama

EPA puts Jefferson County in Zone 2, its middle radon zone, and most reported tests there come back low, though 10.7% of 912 (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

    10.7%

    11.2 pts below AL

    Jefferson
    10.7%
    Alabama
    21.9%

    912 tests, 2008 to 2017

  • Median result

    1.2pCi/L

    Below action level

    Jefferson
    1.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    912

    3rd of 27 by tests

    Jefferson
    912
    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

    22 of 27

    Lowest quarter

    Jefferson
    10.7%
    Colbert
    36.2%

    By share, of 27 with 30+ tests

Read a result for Jefferson County

Starts at Jefferson County's median, 1.2 pCi/L

1.2pCi/L

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

EPA’s reading of 1.2 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. Jefferson County's median reported result, 2008 to 2017.

Interpret this reading

The data

Jefferson County, At a glance

Jefferson County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Jefferson 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Jefferson County, 2008 to 2017, laboratory
Under 2 pCi/L: 66%2 to 4 pCi/L: 23%4 pCi/L and above: 11%

Of 912 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Jefferson County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L60666.4%
2 to 4 pCi/L20822.8%
4 pCi/L and above9810.7%
What these figures count

These are the 912 tests reported to CDC for Jefferson 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

Jefferson County, Compared

Jefferson County radon figures, compared

Calculated by Radon411

Jefferson County reports fewer high tests than Alabama overall. 10.7% of its 912 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 11.2 points below the 21.9% pooled from 65 Alabama counties.

Ordered from highest share down, it comes 22nd 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%; Jefferson County sits 25.0 points below it.

Next door, the shares run from 8.5% in Tuscaloosa County to 14.0% in St. Clair County, with Tuscaloosa County below Jefferson County. Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 10.7% share point the same way here.

Half the tests came in under 1.2 pCi/L and half over it; the single highest reached 24.6 pCi/L. The rest split 66.4% under 2 pCi/L and 22.8% from 2 to 4 (Alabama: 54.3% and 23.8%).

CDC's ten-year totals for Jefferson County went from 841 tests (2005 to 2014) to 912 (2008 to 2017), the share going from 11.2% to 10.7%.

Jefferson County against Alabama, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Jefferson County
Jefferson County91210.7%1.2 pCi/LThis county
Alabama, pooled65 counties, pooled12,56921.9%Not pooled+11.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+25.0 points
Colbert Countyhighest in the state87136.2%2.7 pCi/L+25.5 points
Baldwin Countylowest in the state310.0%1.0 pCi/L−10.7 points
Walker County, ALborders it1533.3%1.4 pCi/L+22.6 points
Bibb County, ALborders it425.0%2.5 pCi/L+14.3 points
St. Clair County, ALborders it9314.0%1.2 pCi/L+3.3 points
Blount County, ALborders it4413.6%2.0 pCi/L+2.9 points
Shelby County, ALborders it37311.3%1.3 pCi/L+0.6 points
Tuscaloosa County, ALborders it828.5%1.4 pCi/L−2.2 points
Where Jefferson County's reported results fell, 2008 to 2017, laboratory, beside Alabama and the United States
ResultJefferson County testsJefferson County shareAlabama shareU.S. shareAgainst Alabama
Under 2 pCi/L60666.4%54.3%39.6%+12.1 points
2 to 4 pCi/L20822.8%23.8%24.7%−1.0 points
4 pCi/L and above9810.7%21.9%35.7%−11.2 points
Jefferson 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
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
Baldwin County27 of 27310.0%1.0 pCi/L
Jefferson County ten-year laboratory totals, against Alabama's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestAlabama, pooledChange from the row before
2008 to 201791210.7%1.2 pCi/L24.6 pCi/L21.9%−0.2 points
2007 to 201693310.9%1.2 pCi/L19.5 pCi/L22.0%+0.3 points
2006 to 201590410.6%1.3 pCi/L19.5 pCi/L22.0%−0.6 points
2005 to 201484111.2%1.3 pCi/L19.5 pCi/L22.4%First on file

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

Jefferson County, Geology

The ground under Jefferson County

Predicted

USGS's geologic map puts all of Jefferson County's mapped land in one class: moderate radon potential. The map puts 52.7% of Jefferson County in the area it calls Appalachian Plateau and 47.3% in Valley and Ridge. USGS gives both a radon index of 9, in the moderate band (9 to 11).

USGS's geologic areas under Jefferson County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Appalachian PlateauLimestone, sandstone, carbonaceous shale, coalModerate952.7%
Valley and RidgeChattanooga black shale, Cambrian-Ordovician limestone and sandstone.Moderate947.3%

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

Jefferson County beside the ground around it

Across Alabama 14.3% of the land is rated high; none of Jefferson County's is. Of the 6 counties that border it, 1 has more high-potential ground, Shelby County the most at 8.0%.

Share of land by USGS radon potential: Jefferson County, the 6 counties bordering it and Alabama
AreaEPA zoneLow potentialModerate potentialHigh potential
Jefferson CountyZone 2None100%None
Shelby CountyZone 2None92.0%8.0%
Walker CountyZone 2None100%None
St. Clair CountyZone 2None100%None
Bibb CountyZone 2None100%None
Blount CountyZone 2None100%None
Tuscaloosa CountyZone 2None100%None
Alabama67 counties, pooled by land areaVaries35.2%50.4%14.3%

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

Local help

Jefferson County, Local resources

Radon testing and mitigation in Jefferson County

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

What it means

Jefferson County, Questions

Questions about radon in Jefferson County

Are radon levels high in Jefferson County?

Over the 2008 to 2017 laboratory totals, 10.7% of the radon tests reported to CDC for Jefferson County, Alabama were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.2 pCi/L. Of 27 Alabama counties with 30 or more tests for the same period, 21 reported a higher share; pooled, the state comes to 21.9%.

Which counties border Jefferson County?

Jefferson County borders 6 counties: Shelby County, Walker County, St. Clair County, Bibb County, Blount County and Tuscaloosa County.

Products

Jefferson County, Products

Testing a home in Jefferson County

In Jefferson County, 10.7% of 912 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 Jefferson County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Jefferson County homes, compared

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Jefferson County, Bordering counties

Counties bordering Jefferson County

Calculated by Radon411

Jefferson County, Cities and towns

Cities and towns in Jefferson County

About 665,742 people live in Jefferson County by the Census Bureau's estimate for July 1, 2025, 8,978 fewer than in 2020 (−1.3%). That works out to 599 people per square mile of land. Birmingham, the largest place on its list (195,893 residents in all), extends beyond Jefferson County, so no share of the total is worked out for it. Reported testing is thin here: 912 tests over 2008 to 2017, or 1.4 for every 1,000 residents (2025 estimate), where Alabama as a whole comes to 2.4.

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

The 12 largest cities and towns in Jefferson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Birminghamextends beyond Jefferson County195,893−2.2%Counted whole
Hooverextends beyond Jefferson County93,550+1.0%Counted whole
Vestavia Hillsextends beyond Jefferson County38,306−2.3%Counted whole
Homewood28,118+2.6%4.2%
Trussvilleextends beyond Jefferson County27,273+4.0%Counted whole
Bessemer24,984−3.7%3.8%
Helenaextends beyond Jefferson County23,388+4.9%Counted whole
Mountain Brook21,661−3.8%3.3%
Gardendale16,425+0.1%2.5%
Hueytown16,159−3.7%2.4%
Center Point15,538−4.8%2.3%
Irondale13,545+0.5%2.0%
  • Leeds (part)
  • Clay
  • Fairfield
  • Pleasant Grove
  • Fultondale
  • Pinson
  • Tarrant
  • Midfield
  • Kimberly
  • Argo (part)
  • Adamsville
  • Lake View (part)
  • Warrior
  • Sumiton (part)
  • Morris
  • Brighton
  • Lipscomb
  • Graysville
  • Sylvan Springs
  • Brookside
  • Mulga
  • Trafford (part)
  • West Jefferson
  • County Line (part)
The other 3 places in Jefferson County
  • Maytown
  • North Johns
  • Cardiff

39 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 Jefferson County is counted whole, so it has no share.

Jefferson County, Homes

Homes in Jefferson County

Of Jefferson County's 309,542 homes, 69% are detached houses, against 69% across Alabama; 21% are in buildings of five or more homes. The homes are older than Alabama's as a whole: half were built before 1975 (1985 for Alabama), and 28% date from before 1960. 64% of occupied homes are lived in by their owner (Alabama: 70%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Jefferson County, Alabama, 2019 to 2023
HomesJefferson CountyAlabama
Housing units309,5422,316,192
Detached houses69%69%
In buildings of 5 or more21%12%
Mobile homes3%13%
Built before 196028%16%
Built since 200020%27%
Middle year built19751985
Owner-occupied64%70%

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