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Radon Levels in Brazos County, Texas

EPA puts Brazos County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 47 (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

    0.0%

    10.2 pts below TX

    Brazos
    0.0%
    Texas
    10.2%

    47 tests, 2008 to 2017

  • Median result

    0.5pCi/L

    Below action level

    Brazos
    0.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    47

    18th of 22 by tests

    Brazos
    47
    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

    19 of 22

    Lowest quarter

    Brazos
    0.0%
    Randall
    69.0%

    By share, of 22 with 30+ tests

Read a result for Brazos County

Starts at Brazos County's median, 0.5 pCi/L

0.5pCi/L

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

EPA’s reading of 0.5 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. Brazos County's median reported result, 2008 to 2017.

Interpret this reading

The data

Brazos County, At a glance

Brazos County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Brazos 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Brazos County, 2008 to 2017, laboratory
Under 2 pCi/L: 92%2 to 4 pCi/L: 8%4 pCi/L and above: 0%

Of 47 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Brazos County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4391.5%
2 to 4 pCi/L48.5%
4 pCi/L and above00.0%
What these figures count

These are the 47 tests reported to CDC for Brazos 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

Brazos County, Compared

Brazos County radon figures, compared

Calculated by Radon411

Only 0 of 47 radon tests reported for Brazos County over the 2008 to 2017 laboratory totals reached 4 pCi/L (0.0%). The median result, 0.5 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 2.3 pCi/L.

Across 138 Texas counties pooled together, 10.2% of tests reached that level, so Brazos County runs 10.2 points below its state. Against the national pool of 35.7%, the gap is 35.7 points lower. Its place in the state: 19th of 22 Texas counties with 30 or more tests for the same period.

Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 0.0% share point the same way here.

Below the action level, 43 tests (91.5%) came in under 2 pCi/L, against 80.3% statewide, and 4 tests (8.5%) fell between 2 and 4, against 9.6% statewide. USGS geology rates 100% of the county's land low radon potential.

CDC's ten-year totals for Brazos County went from 54 tests (2005 to 2014) to 47 (2008 to 2017), the share going from 0.0% to 0.0%.

Brazos County against Texas, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Brazos County
Brazos County470.0%0.5 pCi/LThis county
Texas, pooled138 counties, pooled4,61510.2%Not pooled+10.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+35.7 points
Randall Countyhighest in the state8769.0%6.1 pCi/L+69.0 points
Nueces Countylowest in the state430.0%0.6 pCi/LLevel
Madison County, TXborders it10.0%1.5 pCi/LLevel
Robertson County, TXborders it70.0%0.8 pCi/LLevel
Grimes County, TXborders it10.0%0.1 pCi/LLevel
Where Brazos County's reported results fell, 2008 to 2017, laboratory, beside Texas and the United States
ResultBrazos County testsBrazos County shareTexas shareU.S. shareAgainst Texas
Under 2 pCi/L4391.5%80.3%39.6%+11.2 points
2 to 4 pCi/L48.5%9.6%24.7%−1.1 points
4 pCi/L and above00.0%10.2%35.7%−10.2 points
Brazos 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
Brazoria County12 of 22326.3%0.3 pCi/L
Smith County13 of 22525.8%0.8 pCi/L
Montgomery County14 of 221883.2%0.8 pCi/L
Harris County15 of 227332.9%0.4 pCi/L
Fort Bend County16 of 221052.9%0.2 pCi/L
Williamson County17 of 221031.9%0.7 pCi/L
Midland County18 of 221001.0%0.7 pCi/L
Galveston County19 of 22730.0%0.2 pCi/L
El Paso County19 of 22570.0%0.7 pCi/L
Brazos County19 of 22470.0%0.5 pCi/L
Nueces County19 of 22430.0%0.6 pCi/L
Brazos County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 2017470.0%0.5 pCi/L2.3 pCi/L10.2%Level
2007 to 2016490.0%0.2 pCi/L2.3 pCi/L10.4%Level
2006 to 2015530.0%0.5 pCi/L2.3 pCi/L11.0%Level
2005 to 2014540.0%0.5 pCi/L2.3 pCi/L10.6%First on file

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

Brazos County, Geology

The ground under Brazos County

Predicted

USGS's geologic map puts all of Brazos County's mapped land in one class: low radon potential. The map puts 91.9% of Brazos County in the area it calls East Texas Province and 8.1% in Coastal Plain. USGS gives the first a radon index of 6 and the second 7, both in the low band (5 to 8).

USGS's geologic areas under Brazos County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
East Texas ProvinceCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low691.9%
Coastal PlainCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low78.1%

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

Brazos County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Brazos County's is. None of the 6 counties that border it has any moderate-potential ground either.

Share of land by USGS radon potential: Brazos County, the 6 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Brazos CountyZone 3100%NoneNone
Burleson CountyZone 3100%NoneNone
Grimes CountyZone 3100%NoneNone
Robertson CountyZone 3100%NoneNone
Washington CountyZone 3100%NoneNone
Madison CountyZone 3100%NoneNone
Leon CountyZone 3100%NoneNone
Texas254 counties, pooled by land areaVaries72.4%26.8%0.5%

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

Local help

Brazos County, Local resources

Radon testing and mitigation in Brazos 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

Brazos County, Questions

Questions about radon in Brazos County

Are radon levels high in Brazos County?

Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Brazos County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.5 pCi/L. Of 22 Texas counties with 30 or more tests for the same period, 18 reported a higher share; pooled, the state comes to 10.2%.

Which counties border Brazos County?

Brazos County borders 6 counties: Burleson County, Grimes County, Robertson County, Washington County, Madison County and Leon County.

Products

Brazos County, Products

Testing a home in Brazos County

In Brazos County, 0.0% of 47 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 Brazos County.

Test kits and monitors3

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Best radon monitors for Brazos County homes, compared

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Brazos County, Bordering counties

Counties bordering Brazos County

Calculated by Radon411

Brazos County, Cities and towns

Cities and towns in Brazos County

Brazos County is growing: the Census Bureau puts it at 249,088 residents on July 1, 2025, up 6.2% from 234,527 in 2020. That works out to 425 people per square mile of land. College Station alone is home to 127,472 of them, 51.2% of the total. CDC's 47 reported tests for 2008 to 2017 work out to 0.2 per 1,000 residents (2025 estimate), close to Texas' 0.1.

From College Station to Wixon Valley, CDC publishes no figure by town: each reads Brazos County's.

The cities and towns in Brazos County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
College Station127,472+5.5%51.2%
Bryan91,996+9.1%36.9%
Navasotaextends beyond Brazos County9,904+28.2%Counted whole
Kurten395−0.5%0.2%
Wixon Valley228LevelUnder 0.1%

5 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). A place that extends beyond Brazos County is counted whole, so it has no share.

Brazos County, Homes

Homes in Brazos County

Fewer than six in ten of Brazos County's 99,118 homes are detached houses (51%, against 65% across Texas); the rest are attached, in shared buildings or mobile. Half of its homes were built before 1996, close to Texas' 1990: 7% date from before 1960 and 44% from 2000 or later. Most occupied homes here are rented: owners live in 47% (Texas: 63%). A tenant can run a test; a fix is the landlord's to make.

Homes in Brazos County, Texas, 2019 to 2023
HomesBrazos CountyTexas
Housing units99,11811,890,808
Detached houses51%65%
In buildings of 5 or more25%21%
Mobile homes6%7%
Built before 19607%13%
Built since 200044%37%
Middle year built19961990
Owner-occupied47%63%

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