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Radon Levels in Bell County, Texas

EPA puts Bell County in Zone 3, its lowest radon zone, and 16.7% of its 30 reported radon tests (2008 to 2017, laboratory totals) were at or above 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

    16.7%

    6.5 pts above TX

    Bell
    16.7%
    Texas
    10.2%

    30 tests, 2008 to 2017

  • Median result

    1.3pCi/L

    Below action level

    Bell
    1.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    30

    22nd of 22 by tests

    Bell
    30
    Harris
    733

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 3

    Lower potential

    1. 1
    2. 2
    3. Zone 3

    1 highest, 3 lowest

    EPA predicts under 2 pCi/L indoors

  • Rank in Texas

    5 of 22

    Top quarter

    Bell
    16.7%
    Randall
    69.0%

    By share, of 22 with 30+ tests

Read a result for Bell County

Starts at Bell 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. Bell County's median reported result, 2008 to 2017.

Interpret this reading

The data

Bell County, At a glance

Bell County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Bell County as a whole is an average indoor of less than 2 pCi/L (less than 75 Bq/m³). A low zone clears no address in it: homes above EPA's turn up in all three zones.

USGS geologic potential: Low across 82% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Bell County, 2008 to 2017, laboratory
Under 2 pCi/L: 76%2 to 4 pCi/L: 7%4 pCi/L and above: 17%

Of 30 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Bell County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2376.7%
2 to 4 pCi/L26.7%
4 pCi/L and above516.7%
What these figures count

These are the 30 tests reported to CDC for Bell 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

Bell County, Compared

Bell County radon figures, compared

Calculated by Radon411

Bell County's 30 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.3 pCi/L and a maximum of 6.7 pCi/L, and 16.7% reached 4 pCi/L. Texas as a whole (138 Texas counties, pooled) comes to 10.2%: 6.5 points lower than here.

Among its state's counties it ranks 5th of 22 Texas counties with 30 or more tests for the same period. Statewide for the same period, Randall County reported the highest share (69.0%) and Nueces County the lowest (0.0%).

Below the action level, 23 tests (76.7%) came in under 2 pCi/L, against 80.3% statewide, and 2 tests (6.7%) fell between 2 and 4, against 9.6% statewide. CDC's ten-year totals for Bell County went from 38 tests (2005 to 2014) to 30 (2008 to 2017), the share going from 13.2% to 16.7%.

EPA's 1993 zone map puts Bell County in Zone 3, a predicted county average under 2 pCi/L. USGS geology rates 82% of the county's land low radon potential.

Next door, the shares run from 1.9% in Williamson County to 23.3% in McLennan County, with Williamson County below Bell County.

Bell County against Texas, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Bell County
Bell County3016.7%1.3 pCi/LThis county
Texas, pooled138 counties, pooled4,61510.2%Not pooled−6.5 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+19.0 points
Randall Countyhighest in the state8769.0%6.1 pCi/L+52.3 points
Nueces Countylowest in the state430.0%0.6 pCi/L−16.7 points
Burnet County, TXborders it771.4%27.4 pCi/L+54.7 points
McLennan County, TXborders it3023.3%1.1 pCi/L+6.6 points
Williamson County, TXborders it1031.9%0.7 pCi/L−14.8 points
Coryell County, TXborders it40.0%0.8 pCi/L−16.7 points
Where Bell County's reported results fell, 2008 to 2017, laboratory, beside Texas and the United States
ResultBell County testsBell County shareTexas shareU.S. shareAgainst Texas
Under 2 pCi/L2376.7%80.3%39.6%−3.6 points
2 to 4 pCi/L26.7%9.6%24.7%−2.9 points
4 pCi/L and above516.7%10.2%35.7%+6.5 points
Bell County ranked among the 22 Texas counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Randall County1 of 228769.0%6.1 pCi/L
Lubbock County2 of 2212255.7%4.8 pCi/L
McLennan County3 of 223023.3%1.1 pCi/L
Potter County4 of 227423.0%1.4 pCi/L
Bell County5 of 223016.7%1.3 pCi/L
Tarrant County6 of 2228413.0%0.9 pCi/L
Travis County7 of 224269.2%0.9 pCi/L
Dallas County8 of 227288.4%0.9 pCi/L
Collin County9 of 222897.6%1.0 pCi/L
Denton County10 of 221926.8%0.9 pCi/L
Bexar County11 of 222016.5%0.6 pCi/L
Bell County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 20173016.7%1.3 pCi/L6.7 pCi/L10.2%+2.4 points
2007 to 20163514.3%1.1 pCi/L6.7 pCi/L10.4%Level
2006 to 20153514.3%1.1 pCi/L6.7 pCi/L11.0%+1.1 points
2005 to 20143813.2%1.0 pCi/L6.7 pCi/L10.6%First on file

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

Bell County, Geology

The ground under Bell County

Predicted

Most of the ground under Bell County is one class on USGS's geologic map: 82.2% of its land is low radon potential, with 17.8% moderate. The map puts 47.3% of Bell County in the area it calls Central Texas/Gulf Coast Plain and 35.0% in East Texas Province, with one smaller area beside them. USGS gives the first a radon index of 7 and the second 6, both in the low band (5 to 8).

USGS's geologic areas under Bell County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Central Texas/Gulf Coast PlainCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low747.3%
East Texas ProvinceCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low635.0%
Cretaceous Gulfian seriesCretaceous sandstone, shale, limestone, siltstone.Moderate1017.8%

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

Bell County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Bell County's is. Of the 7 counties that border it, 2 have more moderate-potential ground, Burnet County the most at 28.7%.

Share of land by USGS radon potential: Bell County, the 7 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Bell CountyZone 382.2%17.8%None
Williamson CountyZone 384.6%15.4%None
Coryell CountyZone 3100%NoneNone
Falls CountyZone 399.6%0.4%None
Milam CountyZone 3100%NoneNone
McLennan CountyZone 372.0%28.0%None
Burnet CountyZone 371.3%28.7%None
Lampasas CountyZone 398.3%1.7%None
Texas254 counties, pooled by land areaVaries72.4%26.8%0.5%

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

Local help

Bell County, Local resources

Radon testing and mitigation in Bell County

What Texas's program says
Licensing of radon professionals
There are no radon certification requirements for the State of Texas at this time, but the National Radon Proficiency Program lists radon testers and mitigators within Texas that have passed a rigorous national certification program.

What it means

Bell County, Questions

Questions about radon in Bell County

Are radon levels high in Bell County?

Over the 2008 to 2017 laboratory totals, 16.7% of the radon tests reported to CDC for Bell County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.3 pCi/L. Of 22 Texas counties with 30 or more tests for the same period, 4 reported a higher share; pooled, the state comes to 10.2%.

Which counties border Bell County?

Bell County borders 7 counties: Williamson County, Coryell County, Falls County, Milam County, McLennan County, Burnet County and Lampasas County.

Products

Bell County, Products

Testing a home in Bell County

In Bell County, 16.7% of 30 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 10.2% pooled across Texas. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Bell County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Bell County homes, compared

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Bell County, Bordering counties

Counties bordering Bell County

Calculated by Radon411

Bell County, Cities and towns

Cities and towns in Bell County

Bell County is growing: the Census Bureau puts it at 402,248 residents on July 1, 2025, up 8.0% from 372,407 in 2020. That works out to 382 people per square mile of land. Its largest town, Killeen, has 161,883 residents, 40.2% of the total. Reported testing is thin here: 30 tests over 2008 to 2017, or 0.1 for every 1,000 residents (2025 estimate), where Texas as a whole comes to 0.1.

From Killeen to Rogers, CDC publishes no figure by town: each reads Bell County's.

The 12 largest cities and towns in Bell County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Killeen161,883+5.3%40.2%
Temple98,412+18.8%24.5%
Copperas Coveextends beyond Bell County40,118+9.2%Counted whole
Harker Heights35,195+5.9%8.7%
Belton25,964+12.3%6.5%
Nolanville7,983+33.6%2.0%
Morgan's Point Resort4,746+1.6%1.2%
Troy3,585+48.6%0.9%
Salado2,565+7.3%0.6%
Little River-Academy2,020+1.1%0.5%
Bartlettextends beyond Bell County1,678+2.9%Counted whole
Holland1,188+10.0%0.3%
  • Rogers

13 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 Bell County is counted whole, so it has no share.

Bell County, Homes

Homes in Bell County

Of Bell County's 151,858 homes, 64% are detached houses, against 65% across Texas; 14% are in buildings of five or more homes. Half of its homes were built before 1995, close to Texas' 1990: 8% date from before 1960 and 42% from 2000 or later. 56% of occupied homes are lived in by their owner (Texas: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Bell County, Texas, 2019 to 2023
HomesBell CountyTexas
Housing units151,85811,890,808
Detached houses64%65%
In buildings of 5 or more14%21%
Mobile homes6%7%
Built before 19608%13%
Built since 200042%37%
Middle year built19951990
Owner-occupied56%63%

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