2%tests ≥ 4 pCi/L
103tests on record
0.7median pCi/L
Zone 3EPA zone (1993 prediction)

Test results in Williamson County

ResultShareEPA guidance
Below 2 pCi/L88%Below EPA's levels
2 to 4 pCi/L10%Consider fixing
4 pCi/L or more2%EPA recommends fixing

What the data shows

Where Williamson County sits among Texas's 138 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017
0%20%40%60%80%100%

How Williamson County compares

Williamson County has the lowest share of high results among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Burnet County71%Bastrop County62%Bell County17%Travis County9%Williamson County2%Texas 10%
Data table
AreaTests ≥ 4 pCi/LTests
Burnet County71%7
Bastrop County62%13
Bell County17%30
Travis County9%426
Williamson County2%103
Texas (138 counties)10%4,615

Same source as Williamson County. Other bordering counties: Lee County, Milam County.

What it means for your home

About 1 in 52 results in Williamson County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.

Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.

Test your home

Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide

Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.

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Fixing high radon

No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →

About this data

Source: Radon test results from laboratories (CDC Environmental Public Health Tracking Network). Period: 2008–2017. Tests: 103. Read the methodology →

These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.

About this page

Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us