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Radon Levels in Kerr County, Texas

EPA puts Kerr County in Zone 3, its lowest radon zone, and only 9 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

    6.6%

    Bexar County, 65 miles

    Bexar
    6.6%
    Texas
    10.4%

    Share at 4+ pCi/L, 197 tests, 2007 to 2016

  • Ground above low

    None

    27.3 pts below Texas

    Kerr
    0.0%
    Texas
    27.3%

    Share of land USGS rates moderate or high potential

  • Tests reported

    17

    Too few for a share

    Kerr
    17
    Needed
    30

    2006 to 2015, 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 Kerr 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

Kerr County, At a glance

Kerr County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

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

CDC holds 9 reported tests for Kerr County over the 2008 to 2017 laboratory totals, with a median of 0.9 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Kerr County beside the counties around it is how this page reads it.

What these figures count

Only 9 tests were reported to CDC for Kerr 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

Kerr County, Compared

Kerr County radon figures, compared

Calculated by Radon411

CDC's largest figure for Kerr County rests on 17 tests over the 2006 to 2015 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 5.9 points and no rank or comparison is drawn from it. Results reached as high as 6.3 pCi/L, with a middle value of 1.3 pCi/L.

The nearest counties with a figure are Bexar County (65 miles away) at 6.6%, Travis County (96 miles away) at 9.3% and Williamson County (112 miles away) at 2.0%. 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 Kerr 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 Kerr 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
Kendall County, TXborders it771.4%5.7 pCi/L
Gillespie County, TXborders it1020.0%0.8 pCi/L
Kimble County, TXborders it10.0%2.1 pCi/L
The nearest Texas counties to Kerr County with 30 or more tests, 2007 to 2016, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Bexar County65 mi1976.6%0.6 pCi/L
Travis County96 mi4089.3%0.8 pCi/L
Williamson County112 mi982.0%0.7 pCi/L
Bell County130 mi3514.3%1.1 pCi/L
McLennan County164 mi4117.1%1.0 pCi/L
Brazos County187 mi490.0%0.2 pCi/L
Nueces County192 mi450.0%0.6 pCi/L
Midland County202 mi1001.0%0.7 pCi/L
Kerr County ten-year laboratory totals, against Texas' pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTexas, pooledChange from the row before
2008 to 201790.0%0.9 pCi/L2.2 pCi/L10.2%−12.5 points
2007 to 20161612.5%1.1 pCi/L6.3 pCi/L10.4%+0.7 points
2006 to 20151711.8%1.3 pCi/L6.3 pCi/L11.0%Level
2005 to 20141711.8%1.3 pCi/L6.3 pCi/L10.6%First on file

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

Kerr County, Geology

The ground under Kerr County

Predicted

USGS's geologic map puts all of Kerr County's mapped land in one class: low radon potential. All 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 Kerr County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Southern High Plains and PlateausPaleozoic and Mesozoic sandstone, limestone, shale.Low7100%

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

Kerr County beside the ground around it

Across Texas 0.5% of the land is rated high; none of Kerr County's is. Of the 6 counties that border it, 2 have more moderate-potential ground, Gillespie County the most at 13.2%.

Share of land by USGS radon potential: Kerr County, the 6 counties bordering it and Texas
AreaEPA zoneLow potentialModerate potentialHigh potential
Kerr CountyZone 3100%NoneNone
Bandera CountyZone 3100%NoneNone
Real CountyZone 3100%NoneNone
Gillespie CountyZone 386.8%13.2%None
Kendall CountyZone 3100%NoneNone
Kimble CountyZone 398.3%1.7%None
Edwards 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

Kerr County, Local resources

Radon testing and mitigation in Kerr 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

Kerr County, Questions

Questions about radon in Kerr County

Are radon levels high in Kerr County?

Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Kerr County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of the 8 nearest counties with a figure, within 202 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 17.1%.

Which counties border Kerr County?

Kerr County borders 6 counties: Bandera County, Real County, Gillespie County, Kendall County, Kimble County and Edwards County.

Products

Kerr County, Products

Testing a home in Kerr County

No CDC figure names Kerr County; the nearest county with one, Bexar County (65 miles away), reported 6.6% 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 Kerr County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Kerr County homes, compared

Explore

Kerr County, Bordering counties

Counties bordering Kerr County

Calculated by Radon411

Kerr County, Cities and towns

Cities and towns in Kerr County

The Census Bureau estimates 54,037 residents in Kerr County for July 1, 2025, 1,341 more than in 2020 (+2.5%). That works out to 49 people per square mile of land. Its largest town, Kerrville, has 25,578 residents, 47.3% of the total. Together its 2 incorporated places hold 50.8% of those residents; the other 49.2% live outside any of them. Testing is reported here more often than across the state: CDC's 17 reported tests for 2006 to 2015 come to 0.3 for every 1,000 residents (2025 estimate), against 0.1 for Texas.

From Kerrville to Ingram, CDC publishes no figure by town: each reads Kerr County's.

The cities and towns in Kerr County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Kerrville25,578+5.2%47.3%
Ingram1,846+2.1%3.4%

2 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).

Kerr County, Homes

Homes in Kerr County

Of Kerr County's 25,439 homes, 66% are detached houses, against 65% across Texas; 18% are mobile homes. Half of its homes were built before 1987, close to Texas' 1990: 13% date from before 1960 and 29% from 2000 or later. 70% 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 Kerr County, Texas, 2019 to 2023
HomesKerr CountyTexas
Housing units25,43911,890,808
Detached houses66%65%
In buildings of 5 or more9%21%
Mobile homes18%7%
Built before 196013%13%
Built since 200029%37%
Middle year built19871990
Owner-occupied70%63%

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