Arizona · EPA radon zones
Radon risk in Arizona
Zone 2 (moderate — 2-4 pCi/L). Most of Arizona is Zone 2-3 with isolated Zone 1 pockets in NE counties.
The EPA Map of Radon Zones is published as a planning tool — not a prediction of any single home's reading. Even in Zone 3 states, individual basements can test well above the 4 pCi/L action level, and a Zone 1 designation doesn't mean every home is high. Always test the specific home you live in or are buying.
For homes in Arizona, a short-term test ($15-50, 2-7 days) gives a quick baseline, and a long-term test (90+ days) gives the most accurate annual-average reading. Continuous radon monitors are increasingly popular for ongoing surveillance.
Source: EPA Map of Radon Zones