Radon in Arizona well water
In Arizona, radon was detected in 100% of 885 tested private well samples.
Radon is a radioactive gas released from bedrock into well water. It escapes into household air during showers and washing, where inhaling it raises lung cancer risk. EPA has no enforceable water MCL; New Hampshire recommends treatment above 2,000 pCi/L, and many states use 4,000 pCi/L.
Check your radon number
Type the value from your lab report. It is compared to the EPA limit, the same way the full interpretation does it.
Test your Arizona well for radon
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
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Getting it fixed
Book a free in-home water test with a licensed local company, or see the treatment guide for what removes radon.
Where to get a well tested for radon in Arizona: certified labs, state programs and prices.
By county, from individual samples
Public monitoring samples against the EPA limit; counties with at least 30 samples.
| County | Above EPA limit | Samples | Detected | Median | Highest |
|---|---|---|---|---|---|
| Yavapai | no limit | 97 | 100% | 322 | 2,641 pCi/L |
| Graham | no limit | 54 | 100% | 373 | 3,249 pCi/L |
| La Paz | no limit | 94 | 100% | 464 | 10,241 pCi/L |
| Maricopa | no limit | 194 | 100% | 523 | 3,956 pCi/L |
| Mohave | no limit | 97 | 100% | 286 | 4,839 pCi/L |
| Pinal | no limit | 56 | 100% | 363 | 6,757 pCi/L |
| Cochise | no limit | 62 | 100% | 585 | 4,419 pCi/L |
| Pima | no limit | 101 | 99% | 480 | 84,009 pCi/L |
| Navajo | no limit | 39 | 95% | 270 | 250,000 pCi/L |
- Lake Havasu City CCD, Mohave County100% detected of 35
- Kingman CCD, Mohave County100% detected of 37
- Buckeye CCD, Maricopa County100% detected of 86
- Gila Bend CCD, Maricopa County100% detected of 39
- Wickenburg CCD, Maricopa County100% detected of 31
- Phoenix CCD, Maricopa County100% detected of 31
- Congress CCD, Yavapai County100% detected of 47
- Parker CCD, La Paz County100% detected of 94
- Tucson CCD, Pima County99% detected of 69
Sources
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. radon counts and shares are listed on each county and town page with their sources.