Texas: 254 counties covered
Of 254 rated Texas counties, 0 are in EPA's highest radon-potential zone (Zone 1) — but every county page links to testing guidance regardless of zone, because a county rating is a county-wide average, not a reading for any one house.
- Harris County
- Dallas County
- Tarrant County
- Bexar County
- Travis County
- Collin County
- Denton County
- Fort Bend County
- Hidalgo County
- El Paso County
- Montgomery County
- Williamson County
- Cameron County
- Brazoria County
- Bell County
- Galveston County
- Nueces County
- Lubbock County
- Hays County
- Webb County
- McLennan County
- Jefferson County
- Brazos County
- Smith County
- Ellis County
- Johnson County
- Comal County
- Kaufman County
- Guadalupe County
- Midland County
- Parker County
- Ector County
- Randall County
- Grayson County
- Taylor County
- Rockwall County
- Wichita County
- Gregg County
- Tom Green County
- Hunt County
- Liberty County
- Bastrop County
- Potter County
- Bowie County
- Victoria County
- Angelina County
- Henderson County
- Coryell County
- Orange County
- Walker County
- Wise County
- San Patricio County
- Harrison County
- Hood County
- Starr County
- Nacogdoches County
- Van Zandt County
- Waller County
- Anderson County
- Maverick County
- Hardin County
- Navarro County
- Chambers County
- Burnet County
- Medina County
- Wilson County
- Polk County
- Kerr County
- Rusk County
- Cherokee County
- Atascosa County
- Caldwell County
- Kendall County
- Lamar County
- Wood County
- Val Verde County
- Erath County
- Cooke County
- Upshur County
- Wharton County
- Jim Wells County
- Hopkins County
- Hill County
- Fannin County
- Brown County
- Washington County
- Matagorda County
- Grimes County
- Jasper County
- Austin County
- Hale County
- Titus County
- Bee County
- Howard County
- Kleberg County
- Palo Pinto County
- San Jacinto County
- Cass County
- Gillespie County
- Milam County
- Aransas County
- Fayette County
- Uvalde County
- Shelby County
- Lampasas County
- Llano County
- Panola County
- Gaines County
- Bandera County
- Limestone County
- Houston County
- Montague County
- Moore County
- Hockley County
- Colorado County
- Gray County
- Jones County
- Freestone County
- Lavaca County
- Tyler County
- DeWitt County
- Burleson County
- Gonzales County
- Willacy County
- Calhoun County
- Hutchinson County
- Frio County
- Bosque County
- Andrews County
- Deaf Smith County
- Lee County
- Eastland County
- Young County
- Falls County
- Robertson County
- Leon County
- Scurry County
- Jackson County
- Karnes County
- Pecos County
- Callahan County
- Trinity County
- Comanche County
- Nolan County
- Madison County
- Zapata County
- Blanco County
- Rains County
- Camp County
- Lamb County
- Wilbarger County
- Morris County
- Live Oak County
- Reeves County
- Newton County
- Dawson County
- Red River County
- Terry County
- Ward County
- Franklin County
- Clay County
- Somervell County
- Sabine County
- Runnels County
- Ochiltree County
- Marion County
- Parmer County
- Duval County
- Brewster County
- Stephens County
- Jack County
- Zavala County
- Archer County
- Mitchell County
- Hamilton County
- Dimmit County
- Coleman County
- San Augustine County
- Yoakum County
- Dallam County
- McCulloch County
- Winkler County
- Castro County
- Goliad County
- Bailey County
- Swisher County
- Brooks County
- Refugio County
- Childress County
- La Salle County
- Lynn County
- Carson County
- Presidio County
- Delta County
- San Saba County
- Haskell County
- Martin County
- Floyd County
- Crosby County
- Hansford County
- Hartley County
- Wheeler County
- Garza County
- Crane County
- Jim Hogg County
- Mills County
- Kimble County
- Mason County
- Fisher County
- Hudspeth County
- Baylor County
- Hardeman County
- Coke County
- Concho County
- Sutton County
- Knox County
- Donley County
- Kinney County
- Shackelford County
- Reagan County
- Hemphill County
- Upton County
- Lipscomb County
- Hall County
- Crockett County
- Real County
- Sherman County
- Collingsworth County
- Cochran County
- Schleicher County
- Culberson County
- Menard County
- Oldham County
- Armstrong County
- Jeff Davis County
- Dickens County
- Throckmorton County
- Irion County
- Briscoe County
- Sterling County
- Edwards County
- Cottle County
- Stonewall County
- Glasscock County
- Foard County
- Motley County
- Roberts County
- Terrell County
- Kent County
- McMullen County
- Borden County
- Kenedy County
- King County
- Loving County