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Radon Levels in Tarrant County, Texas

EPA puts Tarrant County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 13.0% of 284 (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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    13.0%

    2.8 pts above TX

    Tarrant
    13.0%
    Texas
    10.2%

    284 tests, 2008 to 2017

  • Median result

    0.9pCi/L

    Below action level

    Tarrant
    0.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    284

    5th of 22 by tests

    Tarrant
    284
    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

    6 of 22

    Top quarter

    Tarrant
    13.0%
    Randall
    69.0%

    By share, of 22 with 30+ tests

Read a result for Tarrant County

Starts at Tarrant County's median, 0.9 pCi/L

0.9pCi/L

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

EPA’s reading of 0.9 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. Tarrant County's median reported result, 2008 to 2017.

Interpret this reading

The data

Tarrant County, At a glance

Tarrant County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Tarrant 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 58% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Tarrant County, 2008 to 2017, laboratory
Under 2 pCi/L: 73%2 to 4 pCi/L: 14%4 pCi/L and above: 13%

Of 284 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Tarrant County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L20672.5%
2 to 4 pCi/L4114.4%
4 pCi/L and above3713.0%
What these figures count

These are the 284 tests reported to CDC for Tarrant 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

Tarrant County, Compared

Tarrant County radon figures, compared

Calculated by Radon411

13.0% of its 284 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 2.8 points above the 10.2% pooled from 138 Texas counties.

Ordered from highest share down, it comes 6th of 22 Texas counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Tarrant County sits 22.7 points below it.

Next door, the shares run from 6.8% in Denton County to 8.4% in Dallas County, with Dallas County and Denton County below Tarrant County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 13.0% share point the same way here.

Half the tests came in under 0.9 pCi/L and half over it; the single highest reached 20.6 pCi/L. The rest split 72.5% under 2 pCi/L and 14.4% from 2 to 4 (Texas: 80.3% and 9.6%).

CDC's ten-year totals for Tarrant County went from 287 tests (2005 to 2014) to 284 (2008 to 2017), the share going from 6.6% to 13.0%.

Tarrant County against Texas, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Tarrant County
Tarrant County28413.0%0.9 pCi/LThis county
Texas, pooled138 counties, pooled4,61510.2%Not pooled−2.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+22.7 points
Randall Countyhighest in the state8769.0%6.1 pCi/L+56.0 points
Nueces Countylowest in the state430.0%0.6 pCi/L−13.0 points
Ellis County, TXborders it1266.7%13.5 pCi/L+53.7 points
Parker County, TXborders it1811.1%1.1 pCi/L−1.9 points
Dallas County, TXborders it7288.4%0.9 pCi/L−4.6 points
Denton County, TXborders it1926.8%0.9 pCi/L−6.2 points
Wise County, TXborders it40.0%0.9 pCi/L−13.0 points
Johnson County, TXborders it140.0%0.8 pCi/L−13.0 points
Where Tarrant County's reported results fell, 2008 to 2017, laboratory, beside Texas and the United States
ResultTarrant County testsTarrant County shareTexas shareU.S. shareAgainst Texas
Under 2 pCi/L20672.5%80.3%39.6%−7.8 points
2 to 4 pCi/L4114.4%9.6%24.7%+4.8 points
4 pCi/L and above3713.0%10.2%35.7%+2.8 points
Tarrant 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
Tarrant County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 201728413.0%0.9 pCi/L20.6 pCi/L10.2%+2.4 points
2007 to 201631210.6%0.9 pCi/L20.6 pCi/L10.4%+1.9 points
2006 to 20153008.7%0.9 pCi/L20.6 pCi/L11.0%+2.1 points
2005 to 20142876.6%0.9 pCi/L20.6 pCi/L10.6%First on file

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

Tarrant County, Geology

The ground under Tarrant County

Predicted

USGS's geologic map splits Tarrant County: 57.5% of its land is low radon potential and 42.5% moderate. The map puts 57.5% of Tarrant County in the area it calls Central Texas/Gulf Coast Plain and 42.5% in Cretaceous Gulfian series. USGS gives the first a radon index of 7, in the low band (5 to 8), and the second 10, in the moderate band (9 to 11).

USGS's geologic areas under Tarrant 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.Low757.5%
Cretaceous Gulfian seriesCretaceous sandstone, shale, limestone, siltstone.Moderate1042.5%

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

Tarrant County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Tarrant County's is. Of the 6 counties that border it, 3 have more moderate-potential ground, Dallas County the most at 64.8%.

Share of land by USGS radon potential: Tarrant County, the 6 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Tarrant CountyZone 357.5%42.5%None
Johnson CountyZone 346.0%54.0%None
Parker CountyZone 3100%NoneNone
Dallas CountyZone 335.2%64.8%None
Denton CountyZone 349.0%51.0%None
Wise CountyZone 3100%NoneNone
Ellis CountyZone 358.7%41.3%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

Tarrant County, Local resources

Radon testing and mitigation in Tarrant 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

Tarrant County, Questions

Questions about radon in Tarrant County

Are radon levels high in Tarrant County?

Over the 2008 to 2017 laboratory totals, 13.0% of the radon tests reported to CDC for Tarrant County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of 22 Texas counties with 30 or more tests for the same period, 5 reported a higher share; pooled, the state comes to 10.2%.

Which counties border Tarrant County?

Tarrant County borders 6 counties: Johnson County, Parker County, Dallas County, Denton County, Wise County and Ellis County.

Products

Tarrant County, Products

Testing a home in Tarrant County

In Tarrant County, 13.0% of 284 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 Tarrant County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Tarrant County homes, compared

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Tarrant County, Bordering counties

Counties bordering Tarrant County

Calculated by Radon411

Tarrant County, Cities and towns

Cities and towns in Tarrant County

Tarrant County is growing: the Census Bureau puts it at 2,248,466 residents on July 1, 2025, up 6.3% from 2,116,194 in 2020. Packed into its land, that is 2,599 people per square mile. Fort Worth, the largest place on its list (1,028,117 residents in all), extends beyond Tarrant County, so no share of the total is worked out for it. CDC's 284 reported tests for 2008 to 2017 work out to 0.1 per 1,000 residents (2025 estimate), close to Texas' 0.1.

From Fort Worth to Westover Hills, CDC publishes no figure by town: each reads Tarrant County's.

The 12 largest cities and towns in Tarrant County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Fort Worthextends beyond Tarrant County1,028,117+11.3%Counted whole
Arlington402,134+2.0%17.9%
Grand Prairieextends beyond Tarrant County209,434+6.8%Counted whole
Mansfieldextends beyond Tarrant County84,444+16.0%Counted whole
Flower Moundextends beyond Tarrant County79,540+4.0%Counted whole
North Richland Hills70,843+0.8%3.2%
Euless60,008−1.7%2.7%
Burlesonextends beyond Tarrant County56,907+18.6%Counted whole
Grapevineextends beyond Tarrant County50,714−0.1%Counted whole
Bedford47,958−3.7%2.1%
Keller46,078+0.8%2.0%
Haltom City45,542−1.0%2.0%
  • Hurst
  • Southlake (part)
  • Saginaw
  • Colleyville
  • Benbrook
  • Watauga
  • Crowley (part)
  • White Settlement
  • Azle (part)
  • Forest Hill
  • Trophy Club (part)
  • Roanoke (part)
  • Kennedale
  • Richland Hills
  • River Oaks
  • Everman
  • Sansom Park
  • Haslet (part)
  • Lake Worth
  • Reno (part)
  • Edgecliff Village
  • Westworth Village
  • Pelican Bay
  • Pantego
The other 6 places in Tarrant County
  • Blue Mound
  • Dalworthington Gardens
  • Westlake (part)
  • Lakeside
  • Newark (part)
  • Westover Hills

42 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 Tarrant County is counted whole, so it has no share.

Tarrant County, Homes

Homes in Tarrant County

Of Tarrant County's 827,874 homes, 66% are detached houses, against 65% across Texas; 24% are in buildings of five or more homes. Half of its homes were built before 1989, close to Texas' 1990: 13% date from before 1960 and 34% from 2000 or later. 59% 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 Tarrant County, Texas, 2019 to 2023
HomesTarrant CountyTexas
Housing units827,87411,890,808
Detached houses66%65%
In buildings of 5 or more24%21%
Mobile homes2%7%
Built before 196013%13%
Built since 200034%37%
Middle year built19891990
Owner-occupied59%63%

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