Arizona Cities Ranked by Indoor Radon Levels
Measured averages from Airthings devices across Arizona, USA. Action level: 4 pCi/L — the threshold at which remediation is recommended.
Sierra Vista has the highest measured indoor radon in Arizona at 4.0 pCi/L, based on Airthings measurements across 42 cities.
Updated August 16, 2026
Highest city
4.0pCi/L
Sierra Vista
Arizona city average
1.6pCi/L
across 42 cities
Above action level
0/ 42
cities
| # | Location | Avg level | Monitors | vs action level |
|---|---|---|---|---|
| 1 | Sierra Vista | 4.0 pCi/L | 9 | 1.0× under |
| 2 | Flagstaff | 3.2 pCi/L | 82 | 0.8× under |
| 3 | Prescott | 3.0 pCi/L | 35 | 0.8× under |
| 4 | Carefree | 2.9 pCi/L | 40 | 0.7× under |
| 5 | San Carlos | 2.9 pCi/L | 10 | 0.7× under |
| 6 | Scottsdale | 2.5 pCi/L | 37 | 0.6× under |
| 7 | Mountainaire | 2.4 pCi/L | 9 | 0.6× under |
| 8 | Tempe Junction | 2.3 pCi/L | 24 | 0.6× under |
| 9 | Green Valley | 2.1 pCi/L | 9 | 0.5× under |
| 10 | Tempe | 2.1 pCi/L | 11 | 0.5× under |
| 11 | West Sedona | 1.8 pCi/L | 8 | 0.5× under |
| 12 | Paradise Valley | 1.8 pCi/L | 91 | 0.5× under |
| 13 | Mesa | 1.8 pCi/L | 26 | 0.4× under |
| 14 | Fountain Hills | 1.7 pCi/L | 28 | 0.4× under |
| 15 | Gilbert | 1.6 pCi/L | 56 | 0.4× under |
| 16 | Prescott Valley | 1.6 pCi/L | 6 | 0.4× under |
| 17 | Glendale | 1.6 pCi/L | 24 | 0.4× under |
| 18 | Sahuarita | 1.6 pCi/L | 9 | 0.4× under |
| 19 | Anthem | 1.6 pCi/L | 15 | 0.4× under |
| 20 | Peoria | 1.6 pCi/L | 26 | 0.4× under |
| 21 | Queen Creek | 1.5 pCi/L | 48 | 0.4× under |
| 22 | Apache Junction | 1.5 pCi/L | 17 | 0.4× under |
| 23 | Sun Lakes | 1.4 pCi/L | 21 | 0.4× under |
| 24 | Maricopa | 1.4 pCi/L | 7 | 0.3× under |
| 25 | Goodyear | 1.4 pCi/L | 9 | 0.3× under |
| 26 | Tanque Verde | 1.3 pCi/L | 15 | 0.3× under |
| 27 | Tortolita | 1.3 pCi/L | 10 | 0.3× under |
| 28 | Laveen | 1.3 pCi/L | 6 | 0.3× under |
| 29 | Oro Valley | 1.2 pCi/L | 9 | 0.3× under |
| 30 | Sun City | 1.2 pCi/L | 11 | 0.3× under |
| 31 | Catalina Foothills | 1.2 pCi/L | 18 | 0.3× under |
| 32 | Casas Adobes | 1.1 pCi/L | 11 | 0.3× under |
| 33 | Chandler | 1.1 pCi/L | 49 | 0.3× under |
| 34 | Flowing Wells | 1.0 pCi/L | 20 | 0.3× under |
| 35 | Phoenix | 1.0 pCi/L | 63 | 0.2× under |
| 36 | Cave Creek | 1.0 pCi/L | 13 | 0.2× under |
| 37 | Guadalupe | 0.9 pCi/L | 25 | 0.2× under |
| 38 | Tolleson | 0.9 pCi/L | 7 | 0.2× under |
| 39 | Surprise | 0.8 pCi/L | 12 | 0.2× under |
| 40 | Tucson | 0.7 pCi/L | 12 | 0.2× under |
| 41 | Sun City West | 0.6 pCi/L | 17 | 0.1× under |
| 42 | Citrus Park | 0.4 pCi/L | 12 | 0.1× under |