Radon zones in Arizona
Last updated
EPA’s Map of Radon Zones places 15 Arizona counties in its three radon potential zones: 0 in Zone 1 (highest), 15 in Zone 2 (moderate), and 0 in Zone 3 (low).
What this means for Arizona homes
Most Arizona counties fall in Zone 2. EPA predicts moderate average indoor levels (2 to 4 pCi/L) across much of Arizona. Many homes will be below the action level, but many will not, and only a test can tell which.
EPA’s guidance is the same everywhere: test your home, fix it if the level is 4 pCi/L or higher, and consider fixing between 2 and 4 pCi/L. The zone map is from 1993 and should not be used to decide whether a single home needs testing.
Arizona radon program
EPA lists the following state contact for Arizona: AZ Department of Health Services – Bureau of Radiation Control, phone 602-255-4850. Website: azdhs.gov/licensing/radiation-regulatory/index.php#radon-about. State programs can tell you about local testing data, free or discounted test kits, disclosure rules for home sales, and credentialed radon professionals.
Arizona counties and their EPA radon zones
| County | EPA radon zone |
|---|---|
| Apache County | Zone 2 |
| Cochise County | Zone 2 |
| Coconino County | Zone 2 |
| Gila County | Zone 2 |
| Graham County | Zone 2 |
| Greenlee County | Zone 2 |
| La Paz County | Zone 2 |
| Maricopa County | Zone 2 |
| Mohave County | Zone 2 |
| Navajo County | Zone 2 |
| Pima County | Zone 2 |
| Pinal County | Zone 2 |
| Santa Cruz County | Zone 2 |
| Yavapai County | Zone 2 |
| Yuma County | Zone 2 |
County names follow the 2020 Census. Zones from the EPA Map of Radon Zones (text version). Rows marked “zone of” use the zone EPA gave the predecessor or surrounding county.
Next steps: read how to test your home, check a result with the level calculator, or look up a single address by ZIP code.