Rankings · Place

Lowest radon potential by state

EPA radon potential zone.

This measure has no better end. The order describes the states, it does not rank them — see the other direction.

EPA county screening guidance, not a measurement for any individual home. Zone 1 is the highest potential and average indoor levels may exceed 4 pCi/L; Zone 2 is moderate, roughly 2–4 pCi/L; Zone 3 is lower, below 2 pCi/L. State profiles show the most-populous official county zone; the U.S. view shows the population-weighted share of residents in the selected zone. County shading identifies counties in that zone. EPA says all homes should be tested, regardless of zone.

  1. 1AlaskaZone 0
  2. 2ArkansasZone 0
  3. 3ArizonaZone 0
  4. 4District of ColumbiaZone 0
  5. 5DelawareZone 0
  6. 6FloridaZone 0
  7. 7HawaiiZone 0
  8. 8LouisianaZone 0
  9. 9MississippiZone 0
  10. 10OklahomaZone 0
  11. 11OregonZone 0
  12. 12TexasZone 0
  13. 13VermontZone 0
  14. 14CaliforniaZone 3
  15. 15New HampshireZone 4
  16. 16UtahZone 4
  17. 17North CarolinaZone 6
  18. 18NevadaZone 6
  19. 19South CarolinaZone 10
  20. 20MichiganZone 12
  21. 21WashingtonZone 15
  22. 22MissouriZone 22
  23. 23AlabamaZone 23
  24. 24New YorkZone 23
  25. 25IdahoZone 24
  26. 26New JerseyZone 24
  27. 27IllinoisZone 27
  28. 28Rhode IslandZone 27
  29. 29GeorgiaZone 33
  30. 30West VirginiaZone 39
  31. 31WisconsinZone 42
  32. 32VirginiaZone 44
  33. 33New MexicoZone 45
  34. 34KentuckyZone 45
  35. 35MassachusettsZone 47
  36. 36TennesseeZone 52
  37. 37MarylandZone 52
  38. 38KansasZone 55
  39. 39OhioZone 63
  40. 40ConnecticutZone 67
  41. 41IndianaZone 72
  42. 42South DakotaZone 72
  43. 43PennsylvaniaZone 77
  44. 44MinnesotaZone 81
  45. 45NebraskaZone 83
  46. 46MontanaZone 84
  47. 47MaineZone 89
  48. 48WyomingZone 97
  49. 49ColoradoZone 98
  50. 50IowaZone 100
  51. 51North DakotaZone 100
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<iframe src="https://movermath.com/embed/radon-potential" width="100%" height="420" style="border:0" loading="lazy" title="EPA radon potential zone by state"></iframe>

Source: U.S. Environmental Protection Agency, Map of Radon Zones. · How this is built