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Radon Levels in Aransas County, Texas

EPA puts Aransas County in Zone 3, its lowest radon zone, and only 2 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Highest bordering

    0.0%

    Nueces County

    Nueces
    0.0%

    1 of 4 neighbours have 30+ tests, 2007 to 2016

  • Nearest county

    0.0%

    Nueces County, 47 miles

    Nueces
    0.0%
    Texas
    10.4%

    Share at 4+ pCi/L, 45 tests, 2007 to 2016

  • Ground above low

    None

    27.3 pts below Texas

    Aransas
    0.0%
    Texas
    27.3%

    Share of land USGS rates moderate or high potential

  • Tests reported

    2

    Too few for a share

    Aransas
    2
    Needed
    30

    2008 to 2017, laboratory

  • 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

Read a result for Aransas County

Starts at EPA's action level

4.0pCi/L

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

EPA’s reading of 4.0 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.

Interpret this readingWhat a fix costs

The data

Aransas County, At a glance

Aransas County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Aransas 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 77% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

CDC holds 2 reported tests for Aransas County over the 2008 to 2017 laboratory totals, with a median of 1.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Aransas County beside the counties around it is how this page reads it.

What these figures count

Only 2 tests were reported to CDC for Aransas County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Aransas County, Compared

Aransas County radon figures, compared

Calculated by Radon411

CDC's largest figure for Aransas County rests on 2 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 50.0 points and no rank or comparison is drawn from it. Results reached as high as 2.9 pCi/L, with a middle value of 1.5 pCi/L.

Nueces County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 0.0% of its tests at or above 4 pCi/L. Farther out, Brazoria County (119 miles away) at 6.3%, Fort Bend County (122 miles away) at 3.4% and Bexar County (130 miles away) at 6.6% have figures too. Pooled across 140 Texas counties, 10.4% of reported tests reached that level; across every county in the country with a figure, 35.8%.

Statewide for the same period, Randall County reported the highest share (71.4%) and Nueces County the lowest (0.0%). EPA's 1993 map puts Aransas County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 77% of the county's land low radon potential.

Texas, the United States and the counties around Aransas County, 2007 to 2016, laboratory
AreaTestsAt or above 4 pCi/LMedian
Texas, pooled140 counties, pooled4,54810.4%Not pooled
United States, pooled2,666 counties, pooled1,939,02535.8%Not pooled
Randall Countyhighest in the state8471.4%6.2 pCi/L
Brazos Countylowest in the state490.0%0.2 pCi/L
Refugio County, TXborders it10.0%1.2 pCi/L
San Patricio County, TXborders it10.0%0.2 pCi/L
Nueces County, TXborders it450.0%0.6 pCi/L
The nearest Texas counties to Aransas County with 30 or more tests, 2007 to 2016, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Nueces County47 mi450.0%0.6 pCi/L
Brazoria County119 mi326.3%0.3 pCi/L
Fort Bend County122 mi1173.4%0.2 pCi/L
Bexar County130 mi1976.6%0.6 pCi/L
Galveston County151 mi830.0%0.2 pCi/L
Harris County154 mi7753.1%0.2 pCi/L
Travis County159 mi4089.3%0.8 pCi/L
Montgomery County175 mi857.1%0.6 pCi/L
Aransas County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 201720.0%1.5 pCi/L2.9 pCi/L10.2%Level
2007 to 201620.0%0.1 pCi/L0.1 pCi/L10.4%Level
2006 to 201520.0%0.1 pCi/L0.1 pCi/L11.0%Level
2005 to 201420.0%0.1 pCi/L0.1 pCi/L10.6%First on file

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

Aransas County, Geology

The ground under Aransas County

Predicted

USGS's geologic map puts all of Aransas County's mapped land in one class: low radon potential. 76.8% of it lies in the area the map calls Coastal Plain, to which USGS gives a radon index of 7, in the low band (5 to 8).

USGS's geologic areas under Aransas County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Coastal PlainCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low776.8%

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

Aransas County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Aransas County's is. None of the 4 counties that border it has any moderate-potential ground either.

Share of land by USGS radon potential: Aransas County, the 4 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Aransas CountyZone 376.8%NoneNone
Refugio CountyZone 3100%NoneNone
Calhoun CountyZone 375.2%NoneNone
San Patricio CountyZone 399.7%NoneNone
Nueces CountyZone 393.2%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

Aransas County, Local resources

Radon testing and mitigation in Aransas 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

Aransas County, Questions

Questions about radon in Aransas County

Are radon levels high in Aransas County?

Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Aransas County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.5 pCi/L. Nueces County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 0.0% of its tests at or above 4 pCi/L.

Which counties border Aransas County?

Aransas County borders 4 counties: Refugio County, Calhoun County, San Patricio County and Nueces County.

Products

Aransas County, Products

Testing a home in Aransas County

No CDC figure names Aransas County; the nearest county with one, Nueces County (47 miles away), reported 0.0% of its tests at or above 4 pCi/L over the 2007 to 2016 laboratory totals, the only reading nearby until a test of this home. 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 Aransas County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Aransas County homes, compared

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Aransas County, Bordering counties

Counties bordering Aransas County

Calculated by Radon411

Aransas County, Cities and towns

Cities and towns in Aransas County

Aransas County is growing: the Census Bureau puts it at 26,146 residents on July 1, 2025, up 9.3% from 23,930 in 2020. That works out to 104 people per square mile of land. Corpus Christi, the largest place on its list (317,247 residents in all), extends beyond Aransas County, so no share of the total is worked out for it. Reported testing is thin here: 2 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 Corpus Christi to Fulton, CDC publishes no figure by town: each reads Aransas County's.

The cities and towns in Aransas County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Corpus Christiextends beyond Aransas County317,247−0.3%Counted whole
Rockport11,348+11.9%43.4%
Aransas Passextends beyond Aransas County8,842+5.8%Counted whole
Fulton1,647+7.9%6.3%

4 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 Aransas County is counted whole, so it has no share.

Aransas County, Homes

Homes in Aransas County

Of Aransas County's 15,795 homes, 65% are detached houses, against 65% across Texas; 19% are mobile homes. Half of its homes were built before 1994, close to Texas' 1990: 7% date from before 1960 and 40% from 2000 or later. Owners live in 78% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.

Homes in Aransas County, Texas, 2019 to 2023
HomesAransas CountyTexas
Housing units15,79511,890,808
Detached houses65%65%
In buildings of 5 or more9%21%
Mobile homes19%7%
Built before 19607%13%
Built since 200040%37%
Middle year built19941990
Owner-occupied78%63%

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