- Under 10%
- 10–20%
- 20–30%
- 30–40%
- 40% or more
- No data
Counties
| County | Tests | % ≥ 4 pCi/L | Median (pCi/L) | EPA zone (1993) | Source |
|---|---|---|---|---|---|
| Anderson County | — | — | — | Zone 3 | — |
| Andrews County | — | — | — | Zone 3 | — |
| Angelina County | 3 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Aransas County | 2 | 0% | 1.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Archer County | — | — | — | Zone 3 | — |
| Armstrong County | — | — | — | Zone 2 | — |
| Atascosa County | 1 | 0% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Austin County | 2 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Bailey County | — | — | — | Zone 2 | — |
| Bandera County | — | — | — | Zone 3 | — |
| Bastrop County | 13 | 62% | 6.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Baylor County | — | — | — | Zone 3 | — |
| Bee County | — | — | — | Zone 3 | — |
| Bell County | 30 | 17% | 1.3 | Zone 3 | Radon test results from laboratories through 2017 |
| Bexar County | 201 | 6% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Blanco County | 2 | 0% | 0.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Borden County | — | — | — | Zone 3 | — |
| Bosque County | — | — | — | Zone 3 | — |
| Bowie County | — | — | — | Zone 3 | — |
| Brazoria County | 32 | 6% | 0.3 | Zone 3 | Radon test results from laboratories through 2017 |
| Brazos County | 47 | 0% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Brewster County | 4 | 50% | 3.0 | Zone 2 | Radon test results from laboratories through 2017 |
| Briscoe County | — | — | — | Zone 3 | — |
| Brooks County | — | — | — | Zone 3 | — |
| Brown County | 2 | 0% | 1.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Burleson County | — | — | — | Zone 3 | — |
| Burnet County | 7 | 71% | 27.4 | Zone 3 | Radon test results from laboratories through 2017 |
| Caldwell County | 2 | 0% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Calhoun County | — | — | — | Zone 3 | — |
| Callahan County | — | — | — | Zone 3 | — |
| Cameron County | 27 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Camp County | — | — | — | Zone 3 | — |
| Carson County | 2 | 100% | 36.2 | Zone 2 | Radon test results from laboratories through 2017 |
| Cass County | 1 | 0% | 1.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Castro County | 1 | 0% | 3.6 | Zone 2 | Radon test results from laboratories through 2017 |
| Chambers County | 3 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Cherokee County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Childress County | 1 | 0% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Clay County | — | — | — | Zone 3 | — |
| Cochran County | — | — | — | Zone 3 | — |
| Coke County | — | — | — | Zone 3 | — |
| Coleman County | — | — | — | Zone 3 | — |
| Collin County | 289 | 8% | 1.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Collingsworth County | 1 | 100% | 12.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Colorado County | 1 | 0% | 1.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Comal County | 22 | 5% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Comanche County | — | — | — | Zone 3 | — |
| Concho County | — | — | — | Zone 3 | — |
| Cooke County | 1 | 0% | 1.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Coryell County | 4 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Cottle County | — | — | — | Zone 3 | — |
| Crane County | — | — | — | Zone 3 | — |
| Crockett County | — | — | — | Zone 3 | — |
| Crosby County | — | — | — | Zone 2 | — |
| Culberson County | — | — | — | Zone 2 | — |
| Dallam County | 1 | 100% | 4.2 | Zone 2 | Radon test results from laboratories through 2017 |
| Dallas County | 728 | 8% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Dawson County | 4 | 25% | 3.0 | Zone 3 | Radon test results from laboratories through 2017 |
| DeWitt County | 1 | 0% | 0.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Deaf Smith County | 6 | 83% | 8.2 | Zone 2 | Radon test results from laboratories through 2017 |
| Delta County | — | — | — | Zone 3 | — |
| Denton County | 192 | 7% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Dickens County | — | — | — | Zone 3 | — |
| Dimmit County | — | — | — | Zone 3 | — |
| Donley County | 1 | 100% | 4.0 | Zone 2 | Radon test results from laboratories through 2017 |
| Duval County | — | — | — | Zone 3 | — |
| Eastland County | 2 | 0% | 1.4 | Zone 3 | Radon test results from laboratories through 2017 |
| Ector County | 27 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Edwards County | — | — | — | Zone 3 | — |
| El Paso County | 57 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Ellis County | 12 | 67% | 13.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Erath County | — | — | — | Zone 3 | — |
| Falls County | — | — | — | Zone 3 | — |
| Fannin County | 1 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Fayette County | 6 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Fisher County | — | — | — | Zone 3 | — |
| Floyd County | — | — | — | Zone 2 | — |
| Foard County | — | — | — | Zone 3 | — |
| Fort Bend County | 105 | 3% | 0.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Franklin County | — | — | — | Zone 3 | — |
| Freestone County | 10 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Frio County | — | — | — | Zone 3 | — |
| Gaines County | — | — | — | Zone 3 | — |
| Galveston County | 73 | 0% | 0.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Garza County | — | — | — | Zone 2 | — |
| Gillespie County | 6 | 17% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Glasscock County | — | — | — | Zone 3 | — |
| Goliad County | — | — | — | Zone 3 | — |
| Gonzales County | 6 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Gray County | 3 | 0% | 1.9 | Zone 2 | Radon test results from laboratories through 2017 |
| Grayson County | 20 | 5% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Gregg County | 13 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Grimes County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Guadalupe County | 3 | 0% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Hale County | 11 | 82% | 7.8 | Zone 2 | Radon test results from laboratories through 2017 |
| Hall County | — | — | — | Zone 3 | — |
| Hamilton County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Hansford County | — | — | — | Zone 2 | — |
| Hardeman County | — | — | — | Zone 3 | — |
| Hardin County | 6 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Harris County | 733 | 3% | 0.4 | Zone 3 | Radon test results from laboratories through 2017 |
| Harrison County | 4 | 0% | 0.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Hartley County | 2 | 50% | 6.1 | Zone 2 | Radon test results from laboratories through 2017 |
| Haskell County | — | — | — | Zone 3 | — |
| Hays County | 23 | 17% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Hemphill County | 1 | 0% | 3.9 | Zone 2 | Radon test results from laboratories through 2017 |
| Henderson County | 1 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Hidalgo County | 17 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Hill County | 5 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Hockley County | — | — | — | Zone 2 | — |
| Hood County | 5 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Hopkins County | 1 | 100% | 5.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Houston County | 1 | 0% | 2.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Howard County | 1 | 0% | 1.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Hudspeth County | — | — | — | Zone 2 | — |
| Hunt County | 4 | 25% | 2.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Hutchinson County | 5 | 20% | 2.7 | Zone 2 | Radon test results from laboratories through 2017 |
| Irion County | — | — | — | Zone 3 | — |
| Jack County | — | — | — | Zone 3 | — |
| Jackson County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Jasper County | 2 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Jeff Davis County | 7 | 29% | 1.1 | Zone 2 | Radon test results from laboratories through 2017 |
| Jefferson County | 23 | 4% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Jim Hogg County | — | — | — | Zone 3 | — |
| Jim Wells County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Johnson County | 14 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Jones County | 1 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Karnes County | — | — | — | Zone 3 | — |
| Kaufman County | 6 | 0% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Kendall County | 7 | 71% | 5.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Kenedy County | — | — | — | Zone 3 | — |
| Kent County | — | — | — | Zone 3 | — |
| Kerr County | 9 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Kimble County | 1 | 0% | 2.1 | Zone 3 | Radon test results from laboratories through 2017 |
| King County | — | — | — | Zone 3 | — |
| Kinney County | — | — | — | Zone 3 | — |
| Kleberg County | — | — | — | Zone 3 | — |
| Knox County | — | — | — | Zone 3 | — |
| La Salle County | — | — | — | Zone 3 | — |
| Lamar County | 1 | 0% | 2.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Lamb County | — | — | — | Zone 2 | — |
| Lampasas County | — | — | — | Zone 3 | — |
| Lavaca County | 3 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Lee County | — | — | — | Zone 3 | — |
| Leon County | — | — | — | Zone 3 | — |
| Liberty County | 1 | 0% | 1.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Limestone County | — | — | — | Zone 3 | — |
| Lipscomb County | 1 | 100% | 7.3 | Zone 2 | Radon test results from laboratories through 2017 |
| Live Oak County | — | — | — | Zone 3 | — |
| Llano County | 6 | 0% | 1.5 | Zone 2 | Radon test results from laboratories through 2017 |
| Loving County | — | — | — | Zone 3 | — |
| Lubbock County | 122 | 56% | 4.8 | Zone 2 | Radon test results from laboratories through 2017 |
| Lynn County | — | — | — | Zone 2 | — |
| Madison County | 1 | 0% | 1.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Marion County | — | — | — | Zone 3 | — |
| Martin County | — | — | — | Zone 3 | — |
| Mason County | — | — | — | Zone 2 | — |
| Matagorda County | 6 | 33% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Maverick County | 2 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| McCulloch County | — | — | — | Zone 3 | — |
| McLennan County | 30 | 23% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| McMullen County | — | — | — | Zone 3 | — |
| Medina County | 2 | 0% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Menard County | — | — | — | Zone 3 | — |
| Midland County | 100 | 1% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Milam County | — | — | — | Zone 3 | — |
| Mills County | — | — | — | Zone 3 | — |
| Mitchell County | — | — | — | Zone 3 | — |
| Montague County | 16 | 13% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Montgomery County | 188 | 3% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Moore County | 2 | 100% | 4.7 | Zone 2 | Radon test results from laboratories through 2017 |
| Morris County | 1 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Motley County | — | — | — | Zone 3 | — |
| Nacogdoches County | 6 | 0% | 1.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Navarro County | 6 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Newton County | — | — | — | Zone 3 | — |
| Nolan County | 3 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Nueces County | 43 | 0% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Ochiltree County | 2 | 100% | 12.1 | Zone 2 | Radon test results from laboratories through 2017 |
| Oldham County | — | — | — | Zone 2 | — |
| Orange County | 11 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Palo Pinto County | — | — | — | Zone 3 | — |
| Panola County | 2 | 0% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Parker County | 18 | 11% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Parmer County | 1 | 100% | 10.6 | Zone 2 | Radon test results from laboratories through 2017 |
| Pecos County | — | — | — | Zone 3 | — |
| Polk County | 1 | 100% | 25.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Potter County | 74 | 23% | 1.4 | Zone 2 | Radon test results from laboratories through 2017 |
| Presidio County | — | — | — | Zone 2 | — |
| Rains County | — | — | — | Zone 3 | — |
| Randall County | 87 | 69% | 6.1 | Zone 2 | Radon test results from laboratories through 2017 |
| Reagan County | — | — | — | Zone 3 | — |
| Real County | — | — | — | Zone 3 | — |
| Red River County | — | — | — | Zone 3 | — |
| Reeves County | — | — | — | Zone 2 | — |
| Refugio County | 1 | 0% | 1.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Roberts County | — | — | — | Zone 2 | — |
| Robertson County | 7 | 0% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Rockwall County | 16 | 19% | 1.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Runnels County | 1 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Rusk County | 2 | 0% | 0.4 | Zone 3 | Radon test results from laboratories through 2017 |
| Sabine County | — | — | — | Zone 3 | — |
| San Augustine County | — | — | — | Zone 3 | — |
| San Jacinto County | 3 | 33% | 1.7 | Zone 3 | Radon test results from laboratories through 2017 |
| San Patricio County | — | — | — | Zone 3 | — |
| San Saba County | — | — | — | Zone 3 | — |
| Schleicher County | — | — | — | Zone 3 | — |
| Scurry County | 1 | 100% | 11.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Shackelford County | 1 | 0% | 1.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Shelby County | — | — | — | Zone 3 | — |
| Sherman County | 1 | 0% | 1.3 | Zone 2 | Radon test results from laboratories through 2017 |
| Smith County | 52 | 6% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Somervell County | — | — | — | Zone 3 | — |
| Starr County | 1 | 0% | 1.2 | Zone 3 | Radon test results from laboratories through 2017 |
| Stephens County | 1 | 100% | 6.3 | Zone 3 | Radon test results from laboratories through 2017 |
| Sterling County | — | — | — | Zone 3 | — |
| Stonewall County | — | — | — | Zone 3 | — |
| Sutton County | — | — | — | Zone 3 | — |
| Swisher County | 4 | 100% | 7.8 | Zone 2 | Radon test results from laboratories through 2017 |
| Tarrant County | 284 | 13% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Taylor County | 28 | 7% | 0.8 | Zone 3 | Radon test results from laboratories through 2017 |
| Terrell County | — | — | — | Zone 2 | — |
| Terry County | — | — | — | Zone 3 | — |
| Throckmorton County | — | — | — | Zone 3 | — |
| Titus County | — | — | — | Zone 3 | — |
| Tom Green County | 6 | 33% | 2.0 | Zone 3 | Radon test results from laboratories through 2017 |
| Travis County | 426 | 9% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Trinity County | — | — | — | Zone 3 | — |
| Tyler County | — | — | — | Zone 3 | — |
| Upshur County | 6 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Upton County | — | — | — | Zone 3 | — |
| Uvalde County | — | — | — | Zone 3 | — |
| Val Verde County | — | — | — | Zone 3 | — |
| Van Zandt County | 5 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Victoria County | 5 | 0% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Walker County | 7 | 0% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Waller County | 7 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Ward County | — | — | — | Zone 3 | — |
| Washington County | — | — | — | Zone 3 | — |
| Webb County | 6 | 0% | 0.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Wharton County | 9 | 0% | 0.5 | Zone 3 | Radon test results from laboratories through 2017 |
| Wheeler County | 2 | 0% | 1.4 | Zone 3 | Radon test results from laboratories through 2017 |
| Wichita County | 10 | 0% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Wilbarger County | 1 | 0% | 2.6 | Zone 3 | Radon test results from laboratories through 2017 |
| Willacy County | — | — | — | Zone 3 | — |
| Williamson County | 103 | 2% | 0.7 | Zone 3 | Radon test results from laboratories through 2017 |
| Wilson County | 1 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Winkler County | — | — | — | Zone 3 | — |
| Wise County | 4 | 0% | 0.9 | Zone 3 | Radon test results from laboratories through 2017 |
| Wood County | — | — | — | Zone 3 | — |
| Yoakum County | 3 | 0% | 1.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Young County | — | — | — | Zone 3 | — |
| Zapata County | 2 | 0% | 0.1 | Zone 3 | Radon test results from laboratories through 2017 |
| Zavala County | — | — | — | Zone 3 | — |
Test your home
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