Radon and home risks by county
Radon in Texas
None of Texas's 254 counties is in EPA's highest radon zone; 39 are in Zone 2, with moderate potential. Radon zones describe an area's potential; EPA recommends testing every home regardless of zone.
Zone 1 counties
0
high radon potential
Zone 2 counties
39
moderate potential
Zone 3 counties
215
low potential
Counties with water violations
203
since 2016; 54 with unresolved ones
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Zone 2: moderate potential (39 counties)
| County | Residents | Water systems | Health violations since 2016 | Unresolved |
|---|---|---|---|---|
| Armstrong County | 1,809 | 2 | 0 | 0 |
| Bailey County | 7,031 | 2 | 0 | 0 |
| Brewster County | 9,508 | 6 | 1 | 0 |
| Carson County | 5,822 | 4 | 2 | 0 |
| Castro County | 7,380 | 4 | 1 | 0 |
| Crosby County | 5,030 | 5 | 1 | 0 |
| Culberson County | 2,254 | 2 | 0 | 0 |
| Dallam County | 7,526 | 2 | 20 | 0 |
| Deaf Smith County | 18,495 | 2 | 0 | 0 |
| Donley County | 3,193 | 5 | 0 | 0 |
| Floyd County | 5,042 | 3 | 0 | 0 |
| Garza County | 4,645 | 2 | 5 | 1 |
| Gray County | 20,888 | 5 | 1 | 0 |
| Hale County | 31,953 | 12 | 11 | 1 |
| Hansford County | 5,006 | 3 | 1 | 1 |
| Hartley County | 4,996 | 2 | 0 | 0 |
| Hemphill County | 3,134 | 1 | 0 | 0 |
| Hockley County | 21,505 | 7 | 27 | 0 |
| Hudspeth County | 3,608 | 6 | 16 | 0 |
| Hutchinson County | 19,721 | 7 | 1 | 0 |
| Jeff Davis County | 1,778 | 4 | 3 | 0 |
| Lamb County | 12,687 | 8 | 3 | 0 |
| Lipscomb County | 2,880 | 4 | 1 | 0 |
| Llano County | 23,163 | 20 | 20 | 0 |
| Lubbock County | 327,394 | 31 | 796 | 3 |
| Lynn County | 5,952 | 5 | 189 | 1 |
| Mason County | 3,987 | 1 | 27 | 1 |
| Moore County | 21,872 | 6 | 1 | 0 |
| Ochiltree County | 9,717 | 3 | 1 | 0 |
| Oldham County | 1,823 | 4 | 0 | 0 |
| Parmer County | 9,669 | 4 | 0 | 0 |
| Potter County | 114,649 | 5 | 0 | 0 |
| Presidio County | 5,686 | 5 | 14 | 0 |
| Randall County | 150,547 | 15 | 6 | 0 |
| Reeves County | 11,956 | 4 | 2 | 0 |
| Roberts County | 837 | 2 | 1 | 0 |
| Sherman County | 2,771 | 3 | 0 | 0 |
| Swisher County | 6,877 | 3 | 0 | 0 |
| Terrell County | 718 | 1 | 1 | 0 |
Zone 3: low potential (215 counties)
| County | Residents | Water systems | Health violations since 2016 | Unresolved |
|---|---|---|---|---|
| Anderson County | 59,512 | 24 | 1 | 1 |
| Andrews County | 18,923 | 2 | 4 | 0 |
| Angelina County | 88,094 | 21 | 103 | 2 |
| Aransas County | 25,595 | 9 | 1 | 0 |
| Archer County | 9,155 | 7 | 0 | 0 |
| Atascosa County | 52,783 | 8 | 0 | 0 |
| Austin County | 32,546 | 21 | 3 | 0 |
| Bandera County | 22,830 | 25 | 19 | 0 |
| Bastrop County | 114,931 | 22 | 1 | 0 |
| Baylor County | 3,533 | 2 | 0 | 0 |
| Bee County | 31,226 | 7 | 4 | 0 |
| Bell County | 399,578 | 28 | 25 | 2 |
| Bexar County | 2,127,737 | 42 | 8 | 1 |
| Blanco County | 13,358 | 7 | 13 | 0 |
| Borden County | 557 | 1 | 42 | 0 |
| Bosque County | 19,013 | 26 | 7 | 1 |
| Bowie County | 91,992 | 17 | 1 | 0 |
| Brazoria County | 413,224 | 162 | 87 | 1 |
| Brazos County | 249,624 | 11 | 22 | 0 |
| Briscoe County | 1,494 | 4 | 31 | 0 |
| Brooks County | 6,740 | 2 | 3 | 0 |
| Brown County | 38,631 | 8 | 2 | 0 |
| Burleson County | 20,179 | 23 | 43 | 0 |
| Burnet County | 55,722 | 37 | 201 | 1 |
| Caldwell County | 52,430 | 8 | 1 | 0 |
| Calhoun County | 19,942 | 12 | 24 | 0 |
| Callahan County | 14,615 | 5 | 12 | 0 |
| Cameron County | 431,874 | 21 | 47 | 1 |
| Camp County | 13,164 | 8 | 0 | 0 |
| Cass County | 28,622 | 14 | 26 | 0 |
| Chambers County | 56,179 | 30 | 31 | 1 |
| Cherokee County | 53,223 | 27 | 124 | 0 |
| Childress County | 6,679 | 7 | 0 | 0 |
| Clay County | 10,730 | 8 | 19 | 0 |
| Cochran County | 2,583 | 3 | 5 | 0 |
| Coke County | 3,396 | 4 | 8 | 0 |
| Coleman County | 7,990 | 3 | 7 | 0 |
| Collin County | 1,254,658 | 35 | 3 | 0 |
| Collingsworth County | 2,611 | 4 | 2 | 0 |
| Colorado County | 21,475 | 14 | 1 | 0 |
| Comal County | 201,628 | 32 | 54 | 1 |
| Comanche County | 14,359 | 6 | 7 | 0 |
| Concho County | 3,326 | 3 | 109 | 1 |
| Cooke County | 44,258 | 19 | 5 | 1 |
| Coryell County | 86,370 | 13 | 22 | 0 |
| Cottle County | 1,263 | 2 | 0 | 0 |
| Crane County | 4,594 | 1 | 0 | 0 |
| Crockett County | 2,799 | 1 | 0 | 0 |
| Dallas County | 2,656,028 | 34 | 22 | 1 |
| Dawson County | 11,758 | 4 | 46 | 0 |
| DeWitt County | 20,252 | 4 | 0 | 0 |
| Delta County | 5,647 | 4 | 1 | 0 |
| Denton County | 1,045,120 | 82 | 12 | 2 |
| Dickens County | 1,725 | 4 | 0 | 0 |
| Dimmit County | 8,181 | 7 | 5 | 0 |
| Duval County | 9,585 | 6 | 39 | 0 |
| Eastland County | 18,290 | 13 | 65 | 1 |
| Ector County | 170,022 | 8 | 21 | 0 |
| Edwards County | 1,383 | 2 | 10 | 0 |
| El Paso County | 875,784 | 22 | 15 | 1 |
| Ellis County | 232,387 | 32 | 10 | 0 |
| Erath County | 44,496 | 18 | 22 | 0 |
| Falls County | 17,752 | 10 | 25 | 0 |
| Fannin County | 38,650 | 23 | 1 | 0 |
| Fayette County | 25,488 | 9 | 5 | 0 |
| Fisher County | 3,665 | 4 | 2 | 1 |
| Foard County | 1,053 | 3 | 40 | 0 |
| Fort Bend County | 958,434 | 180 | 0 | 0 |
| Franklin County | 10,912 | 4 | 1 | 0 |
| Freestone County | 20,645 | 20 | 1 | 0 |
| Frio County | 19,520 | 4 | 0 | 0 |
| Gaines County | 22,892 | 4 | 5 | 0 |
| Galveston County | 367,407 | 26 | 19 | 1 |
| Gillespie County | 28,159 | 17 | 7 | 0 |
| Glasscock County | 1,153 | 1 | 0 | 0 |
| Goliad County | 7,221 | 4 | 0 | 0 |
| Gonzales County | 20,040 | 7 | 1 | 0 |
| Grayson County | 150,532 | 40 | 52 | 1 |
| Gregg County | 126,679 | 15 | 11 | 0 |
| Grimes County | 33,448 | 18 | 9 | 0 |
| Guadalupe County | 195,166 | 16 | 7 | 0 |
| Hall County | 2,828 | 7 | 23 | 1 |
| Hamilton County | 8,644 | 2 | 1 | 0 |
| Hardeman County | 3,417 | 7 | 23 | 0 |
| Hardin County | 58,670 | 21 | 5 | 0 |
| Harris County | 5,009,302 | 714 | 54 | 12 |
| Harrison County | 71,370 | 26 | 41 | 1 |
| Haskell County | 5,435 | 9 | 22 | 0 |
| Hays County | 292,029 | 52 | 3 | 1 |
| Henderson County | 87,467 | 62 | 37 | 0 |
| Hidalgo County | 914,820 | 25 | 13 | 3 |
| Hill County | 38,771 | 38 | 7 | 0 |
| Hood County | 69,126 | 51 | 6 | 0 |
| Hopkins County | 38,784 | 14 | 6 | 0 |
| Houston County | 22,197 | 9 | 1 | 0 |
| Howard County | 30,833 | 3 | 19 | 0 |
| Hunt County | 118,729 | 30 | 11 | 0 |
| Irion County | 1,526 | 2 | 1 | 0 |
| Jack County | 9,398 | 3 | 13 | 0 |
| Jackson County | 15,284 | 11 | 1 | 0 |
| Jasper County | 32,907 | 19 | 56 | 0 |
| Jefferson County | 253,948 | 17 | 48 | 0 |
| Jim Hogg County | 4,583 | 1 | 22 | 0 |
| Jim Wells County | 38,886 | 7 | 41 | 2 |
| Johnson County | 210,547 | 57 | 5 | 0 |
| Jones County | 20,850 | 6 | 23 | 0 |
| Karnes County | 15,137 | 5 | 1 | 0 |
| Kaufman County | 197,829 | 34 | 5 | 0 |
| Kendall County | 51,828 | 16 | 11 | 0 |
| Kenedy County | 330 | 2 | 10 | 0 |
| Kent County | 703 | 2 | 34 | 0 |
| Kerr County | 53,900 | 74 | 88 | 1 |
| Kimble County | 4,401 | 2 | 6 | 0 |
| King County | 215 | 1 | 2 | 0 |
| Kinney County | 3,191 | 3 | 0 | 0 |
| Kleberg County | 30,442 | 9 | 41 | 0 |
| Knox County | 3,255 | 8 | 2 | 0 |
| La Salle County | 6,679 | 4 | 1 | 0 |
| Lamar County | 51,249 | 9 | 7 | 0 |
| Lampasas County | 23,539 | 4 | 11 | 0 |
| Lavaca County | 20,605 | 3 | 0 | 0 |
| Lee County | 18,451 | 6 | 7 | 0 |
| Leon County | 16,698 | 15 | 8 | 0 |
| Liberty County | 115,042 | 69 | 4 | 1 |
| Limestone County | 22,569 | 19 | 51 | 2 |
| Live Oak County | 11,967 | 6 | 1 | 0 |
| Loving County | 48 | 1 | 0 | 0 |
| Madison County | 13,877 | 6 | 0 | 0 |
| Marion County | 9,704 | 10 | 11 | 0 |
| Martin County | 5,179 | 2 | 3 | 0 |
| Matagorda County | 36,391 | 26 | 33 | 1 |
| Maverick County | 58,829 | 2 | 5 | 0 |
| McCulloch County | 7,448 | 6 | 420 | 0 |
| McLennan County | 270,358 | 54 | 46 | 1 |
| McMullen County | 565 | 2 | 2 | 0 |
| Medina County | 55,619 | 29 | 6 | 0 |
| Menard County | 1,911 | 1 | 0 | 0 |
| Midland County | 183,587 | 15 | 112 | 2 |
| Milam County | 26,159 | 11 | 1 | 0 |
| Mills County | 4,563 | 3 | 0 | 0 |
| Mitchell County | 8,968 | 5 | 0 | 0 |
| Montague County | 21,890 | 10 | 8 | 0 |
| Montgomery County | 749,613 | 338 | 25 | 1 |
| Morris County | 12,184 | 5 | 0 | 0 |
| Motley County | 1,015 | 3 | 3 | 0 |
| Nacogdoches County | 65,728 | 16 | 7 | 0 |
| Navarro County | 56,533 | 22 | 21 | 1 |
| Newton County | 11,908 | 8 | 0 | 0 |
| Nolan County | 14,182 | 4 | 3 | 1 |
| Nueces County | 353,125 | 12 | 5 | 0 |
| Orange County | 86,115 | 29 | 22 | 0 |
| Palo Pinto County | 30,231 | 13 | 63 | 0 |
| Panola County | 23,022 | 18 | 47 | 0 |
| Parker County | 179,707 | 77 | 219 | 1 |
| Pecos County | 14,712 | 5 | 0 | 0 |
| Polk County | 54,258 | 56 | 180 | 0 |
| Rains County | 13,306 | 6 | 23 | 1 |
| Reagan County | 3,139 | 2 | 1 | 0 |
| Real County | 2,772 | 8 | 4 | 0 |
| Red River County | 11,696 | 7 | 1 | 0 |
| Refugio County | 6,739 | 5 | 0 | 0 |
| Robertson County | 17,659 | 9 | 1 | 0 |
| Rockwall County | 137,044 | 7 | 1 | 0 |
| Runnels County | 9,751 | 5 | 21 | 0 |
| Rusk County | 53,391 | 33 | 12 | 0 |
| Sabine County | 10,058 | 10 | 15 | 0 |
| San Augustine County | 7,767 | 15 | 169 | 0 |
| San Jacinto County | 29,326 | 31 | 2 | 0 |
| San Patricio County | 71,467 | 14 | 5 | 0 |
| San Saba County | 5,508 | 5 | 0 | 0 |
| Schleicher County | 2,302 | 1 | 0 | 0 |
| Scurry County | 16,211 | 4 | 3 | 0 |
| Shackelford County | 3,169 | 3 | 8 | 0 |
| Shelby County | 24,192 | 20 | 104 | 1 |
| Smith County | 249,091 | 37 | 58 | 0 |
| Somervell County | 10,098 | 8 | 0 | 0 |
| Starr County | 66,587 | 9 | 4 | 0 |
| Stephens County | 9,475 | 4 | 0 | 0 |
| Sterling County | 1,387 | 1 | 0 | 0 |
| Stonewall County | 1,235 | 3 | 12 | 0 |
| Sutton County | 3,269 | 1 | 0 | 0 |
| Tarrant County | 2,230,708 | 77 | 7 | 2 |
| Taylor County | 148,813 | 14 | 11 | 0 |
| Terry County | 11,602 | 3 | 55 | 0 |
| Throckmorton County | 1,532 | 1 | 2 | 0 |
| Titus County | 31,547 | 5 | 0 | 0 |
| Tom Green County | 120,103 | 17 | 15 | 3 |
| Travis County | 1,363,767 | 89 | 16 | 0 |
| Trinity County | 14,489 | 18 | 64 | 2 |
| Tyler County | 20,560 | 18 | 7 | 0 |
| Upshur County | 44,050 | 13 | 0 | 0 |
| Upton County | 3,128 | 4 | 16 | 2 |
| Uvalde County | 25,138 | 11 | 4 | 0 |
| Val Verde County | 47,999 | 16 | 20 | 0 |
| Van Zandt County | 65,304 | 21 | 9 | 1 |
| Victoria County | 91,949 | 13 | 41 | 5 |
| Walker County | 83,722 | 23 | 30 | 1 |
| Waller County | 65,109 | 43 | 3 | 1 |
| Ward County | 11,038 | 6 | 0 | 0 |
| Washington County | 37,810 | 10 | 1 | 0 |
| Webb County | 272,823 | 7 | 73 | 0 |
| Wharton County | 42,035 | 13 | 2 | 2 |
| Wheeler County | 4,824 | 5 | 1 | 0 |
| Wichita County | 129,984 | 9 | 1 | 0 |
| Wilbarger County | 12,455 | 8 | 8 | 0 |
| Willacy County | 20,027 | 4 | 5 | 1 |
| Williamson County | 727,480 | 40 | 13 | 0 |
| Wilson County | 55,415 | 16 | 0 | 0 |
| Winkler County | 7,381 | 2 | 0 | 0 |
| Wise County | 81,275 | 44 | 32 | 0 |
| Wood County | 48,742 | 19 | 2 | 0 |
| Yoakum County | 7,581 | 2 | 0 | 0 |
| Young County | 18,236 | 6 | 1 | 1 |
| Zapata County | 13,819 | 4 | 1 | 0 |
| Zavala County | 9,209 | 4 | 0 | 0 |
How to read this table
Water systems counts community systems that list the county in their service area; one system can serve several counties. Health violations are breaches of a legal limit or treatment rule recorded by EPA since January 2016, not paperwork lapses. A violation stays unresolved until the state records it as fixed.
Other states
- Arizona
- California
- Colorado
- Florida
- Idaho
- Illinois
- Iowa
- Michigan
- Minnesota
- New Jersey
- New York
- Ohio
- Pennsylvania
- Utah
Sources: EPA Map of Radon Zones, EPA ECHO Safe Drinking Water Act data (2026Q3, published October 2026), US Census Bureau Vintage 2024 estimates. See the methodology.