zipradar

Topic · EPA Radon Zones

Radon risk zone by county

The EPA Map of Radon Zones classifies every US county into Zone 1 (high risk), Zone 2 (moderate), or Zone 3 (low) based on measured radon levels.

Last verified 2026-04-24 · methodology

What zipradar shows

Pages show the county zone, what the classification means for home testing recommendations, and state-level supplementary data where available.

Refresh cadence

Static 1993 baseline plus state-level supplementary updates. zipradar honors the regulator's publishing cadence; stale data is flagged rather than silently served.

Limitations

Radon is a regional indicator. Address-level radon measurement requires an at-home test kit (often free from state health departments).

Primary source

EPA Radon Zones

Look up radon by ZIP

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