Radon in Idaho well water
In Idaho, radon was detected in 100% of 1,617 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.
Getting it fixed
Book a free in-home water test with a licensed local company, or see the treatment guide for what removes radon.
By county, from individual samples
Public monitoring samples against the EPA limit; counties with at least 30 samples.
| County | Samples | Detected | Above EPA limit | Median | Highest |
|---|---|---|---|---|---|
| Twin Falls | 65 | 100% | no limit | 320 | 4,430 pCi/L |
| Bannock | 34 | 100% | no limit | 482 | 1,900 pCi/L |
| Bingham | 62 | 100% | no limit | 297 | 900 pCi/L |
| Blaine | 34 | 100% | no limit | 875 | 2,610 pCi/L |
| Bonner | 55 | 100% | no limit | 650 | 3,930 pCi/L |
| Butte | 59 | 100% | no limit | 170 | 1,200 pCi/L |
| Canyon | 106 | 100% | no limit | 480 | 3,620 pCi/L |
| Cassia | 35 | 100% | no limit | 490 | 3,880 pCi/L |
| Custer | 54 | 100% | no limit | 1,480 | 8,000 pCi/L |
| Elmore | 33 | 100% | no limit | 480 | 1,900 pCi/L |
| Minidoka | 92 | 100% | no limit | 160 | 1,000 pCi/L |
| Ada | 353 | 100% | no limit | 600 | 2,800 pCi/L |
| Jefferson | 41 | 100% | no limit | 230 | 1,390 pCi/L |
| Kootenai | 30 | 100% | no limit | 759 | 2,940 pCi/L |
| Latah | 30 | 100% | no limit | 465 | 8,040 pCi/L |
- Minidoka CCD, Minidoka County100% detected of 33
- Howe CCD, Butte County100% detected of 36
- Stanley CCD, Custer County100% detected of 35
- Mud Lake-Hamer CCD, Jefferson County100% detected of 34
- Boise City CCD, Ada County100% detected of 227
- Eagle CCD, Ada County100% detected of 57
- Orchard CCD, Ada County100% detected of 40
- Nampa CCD, Canyon County100% detected of 41
- Jerome CCD, Jerome County97% detected of 38
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.