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Radon Levels in Tom Green County, Texas

EPA puts Tom Green County in Zone 3, its lowest radon zone, and only 6 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

  • Nearest county

    1.0%

    Midland County, 98 miles

    Midland
    1.0%
    Texas
    10.4%

    Share at 4+ pCi/L, 100 tests, 2007 to 2016

  • Ground above low

    0.1%

    27.2 pts below Texas

    Tom Green
    0.1%
    Texas
    27.3%

    Share of land USGS rates moderate or high potential

  • Tests reported

    7

    Too few for a share

    Tom Green
    7
    Needed
    30

    2005 to 2014, 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 Tom Green 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

Tom Green County, At a glance

Tom Green County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Tom Green 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 Tom Green County, 2008 to 2017, laboratory

CDC holds 6 reported tests for Tom Green County over the 2008 to 2017 laboratory totals, with a median of 2.0 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Tom Green County beside the counties around it is how this page reads it.

What these figures count

Only 6 tests were reported to CDC for Tom Green 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

Tom Green County, Compared

Tom Green County radon figures, compared

Calculated by Radon411

CDC's largest figure for Tom Green County rests on 7 tests over the 2005 to 2014 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 14.3 points and no rank or comparison is drawn from it. Results reached as high as 21.3 pCi/L, with a middle value of 1.6 pCi/L.

The nearest counties with a figure are Midland County (98 miles away) at 1.0%, Lubbock County (171 miles away) at 57.8% and Travis County (175 miles away) at 9.3%. 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 Tom Green County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 100% of the county's land low radon potential.

Texas, the United States and the counties around Tom Green 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
Nueces Countylowest in the state450.0%0.6 pCi/L
Runnels County, TXborders it10.0%0.7 pCi/L
The nearest Texas counties to Tom Green County with 30 or more tests, 2007 to 2016, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Midland County98 mi1001.0%0.7 pCi/L
Lubbock County171 mi12857.8%4.8 pCi/L
Travis County175 mi4089.3%0.8 pCi/L
Williamson County178 mi982.0%0.7 pCi/L
Bexar County178 mi1976.6%0.6 pCi/L
Bell County178 mi3514.3%1.1 pCi/L
McLennan County193 mi4117.1%1.0 pCi/L
Tarrant County208 mi31210.6%0.9 pCi/L
Tom Green County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 2017633.3%2.0 pCi/L21.3 pCi/L10.2%Level
2007 to 2016633.3%2.0 pCi/L21.3 pCi/L10.4%Level
2006 to 2015633.3%2.0 pCi/L21.3 pCi/L11.0%+4.7 points
2005 to 2014728.6%1.6 pCi/L21.3 pCi/L10.6%First on file

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

Tom Green County, Geology

The ground under Tom Green County

Predicted

Most of the ground under Tom Green County is one class on USGS's geologic map: 99.9% of its land is low radon potential, with 0.1% moderate. 99.4% of it lies in the area the map calls Southern High Plains and Plateaus, to which USGS gives a radon index of 7, in the low band (5 to 8).

USGS's geologic areas under Tom Green County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Southern High Plains and PlateausPaleozoic and Mesozoic sandstone, limestone, shale.Low799.4%
Central TexasCretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite.Low70.5%

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

Tom Green County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Tom Green County's is. Of the 8 counties that border it, 2 have more moderate-potential ground, Reagan County the most at 67.2%.

Share of land by USGS radon potential: Tom Green County, the 8 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Tom Green CountyZone 399.9%0.1%None
Schleicher CountyZone 3100%NoneNone
Concho CountyZone 3100%NoneNone
Irion CountyZone 3100%NoneNone
Coke CountyZone 3100%NoneNone
Runnels CountyZone 3100%NoneNone
Menard CountyZone 3100%NoneNone
Sterling CountyZone 351.5%48.5%None
Reagan CountyZone 332.8%67.2%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

Tom Green County, Local resources

Radon testing and mitigation in Tom Green 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

Tom Green County, Questions

Questions about radon in Tom Green County

Are radon levels high in Tom Green County?

Over the 2008 to 2017 laboratory totals, 33.3% of the radon tests reported to CDC for Tom Green County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. Of the 8 nearest counties with a figure, within 208 miles, the share of tests at or above 4 pCi/L runs from 1.0% to 57.8%.

Which counties border Tom Green County?

Tom Green County borders 8 counties: Schleicher County, Concho County, Irion County, Coke County, Runnels County, Menard County, Sterling County and Reagan County.

Products

Tom Green County, Products

Testing a home in Tom Green County

No CDC figure names Tom Green County; the nearest county with one, Midland County (98 miles away), reported 1.0% 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 Tom Green County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Tom Green County homes, compared

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Tom Green County, Bordering counties

Counties bordering Tom Green County

Calculated by Radon411

Tom Green County, Cities and towns

Cities and towns in Tom Green County

Tom Green County's population has barely moved since 2020: 120,602 residents on July 1, 2025 against 120,185 then, by the Census Bureau's estimates. That works out to 79 people per square mile of land. San Angelo, its one incorporated place, has 100,640 residents, 83.4% of the total. Reported testing is thin here: 7 tests over 2005 to 2014, or 0.1 for every 1,000 residents (2025 estimate), where Texas as a whole comes to 0.1.

San Angelo is the one incorporated place here; CDC publishes no figure by town, so it reads Tom Green County's.

San Angelo, Tom Green County: residents on July 1, 2025
PlaceResidentsSince 2020Share of residents
San Angelo100,640+0.6%83.4%

One incorporated place, 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).

Tom Green County, Homes

Homes in Tom Green County

Of Tom Green County's 51,949 homes, 72% are detached houses, against 65% across Texas; 15% are in buildings of five or more homes. The homes are older than Texas' as a whole: half were built before 1979 (1990 for Texas), and 25% date from before 1960. 67% 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 Tom Green County, Texas, 2019 to 2023
HomesTom Green CountyTexas
Housing units51,94911,890,808
Detached houses72%65%
In buildings of 5 or more15%21%
Mobile homes6%7%
Built before 196025%13%
Built since 200020%37%
Middle year built19791990
Owner-occupied67%63%

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