Radon Levels Guide

Home » Texas » Travis County

Radon in Travis County, TX: Test Results and Levels

Updated November 2026 · Data: CDC National Environmental Public Health Tracking Network (radon test results from laboratories, 2008–2017), EPA Map of Radon Zones · Sources and method

Radon testing laboratories reported 194 pre-mitigation radon tests from buildings in Travis County, Texas between 2008 and 2017, according to the CDC Tracking Network. 9.2% of those tests were at or above the EPA action level of 4 pCi/L, and the median result was 0.9 pCi/L. That is roughly 1 in 11 tested buildings. The county’s share of high results is about the same as the Texas figure of 11.3% and below the U.S. figure of 36.4%. Travis County is in EPA radon Zone 3 (low potential, below 2 pCi/L).

9.2%of tests at or above 4 pCi/L
0.9 pCi/Lmedian test result
3.4 pCi/Laverage (mean) test result
194buildings tested, 2008–2017
389.9 pCi/Lhighest test result
#6 of 19Texas counties by share of high tests
Zone 3EPA radon zone

These are area results, not your home’s level. Homes next to each other can have very different radon levels. The only way to know yours is to test.

Radon test results in Travis County

Test resultTravis CountyTexasUnited States
Below 2 pCi/L76.5%78.4%38.8%
2 to 4 pCi/L14.3%10.3%24.8%
4 pCi/L or higher9.2%11.3%36.4%
Share of pre-mitigation tests by level, 2008–2017. Source: CDC Tracking Network, Radon Tests from Labs.

About 77% of tests in Travis County came back below 2 pCi/L, and 14.3% fell between 2 and 4 pCi/L, where the EPA suggests considering a fix. The average result (3.4 pCi/L) is well above the median (0.9 pCi/L) because a smaller number of very high readings pull the average up; the highest test reported was 389.9 pCi/L.

How Travis County compares with other Texas counties

CountyTests4 pCi/L or higherMedian (pCi/L)
Travis County (this page)1949.2%0.9
Tarrant County19313.0%0.9
Dallas County3818.4%0.9
Collin County1737.6%1.0
Denton County1036.8%0.9
Harris County3002.9%0.4
Counties with at least 100 tests, highest share of high results first. Source: CDC Tracking Network, 2008–2017.

All Texas counties, the radon zone map and state contacts: Radon in Texas.

How to test your home in Travis County

Frequently asked questions

Is radon a problem in Travis County?

9.2% of 194 pre-mitigation radon tests in Travis County from 2008 to 2017 were at or above 4 pCi/L, according to CDC Tracking Network laboratory data. The county is in EPA radon Zone 3. Any home can have high radon, so testing is the only way to know.

What is the average radon level in Travis County?

The median test result in Travis County is 0.9 pCi/L and the mean is 3.4 pCi/L (CDC Tracking Network, 2008–2017). For comparison, the average indoor radon level in U.S. homes is about 1.3 pCi/L, according to the EPA.

How does Travis County compare with the rest of Texas?

Travis County ranks 6 of 19 Texas counties (with at least 20 tests) by the share of tests at or above 4 pCi/L. Statewide, 11.3% of 2,382 laboratory tests reached that level.

Should I test if my neighbor’s result was low?

Yes. Radon depends on the soil and rock under each building and on how the building is built, so two houses on the same street can have very different results.

Sources and method

The CDC National Environmental Public Health Tracking Network collects radon test results from radon testing laboratories and summarizes them by county over 10-year periods; the latest period available is 2008–2017. Numbers describe buildings that were tested (mostly homes tested by their owners), not a random sample of every home, and counties with few tests are less reliable. We only publish county pages where at least 100 buildings were tested. State and U.S. figures on this page are weighted by the number of tests in each county. Data retrieved in November 2026.