Why this exists

"Is radon a risk here" searches mostly turn up either a paid test-kit storefront or a vague national statistic. RadonZoneCheck instead reports what EPA itself already publishes for every county: a Map of Radon Zones rating, and what that rating actually means for one house.

What goes into the number

Every county's zone comes from EPA's own Map of Radon Zones, built from aerial radioactivity, soil parameters, foundation types and geology. Population and location come from the Census Bureau. Both are cited on every county page, and documented in full in the methodology guide.

A county rating, honestly labeled

EPA's map predicts a county-WIDE average, from a 1993 assessment last republished (unchanged) in September 2025 — not a live monitoring network and not a reading for any specific house. This site says so on every page and links to EPA's own guidance to test regardless of zone, rather than implying the zone is an answer by itself.

Who runs this

RadonZoneCheck is an independently run site. It is not affiliated with EPA or any radon testing or mitigation company. Where a page includes a sponsored link or an affiliate programme, that is disclosed on the page itself and in the privacy policy.

How this is written and checked

Every county page on RadonZoneCheck is written by cross-referencing EPA's Map of Radon Zones and Census data directly, not paraphrased from other radon sites. Pages stick to EPA's own published figures — zone ratings, the action level, national averages, mitigation cost ranges — and never make a health or cancer-risk claim about any specific home, since a county zone cannot support one. Corrections reported through the contact page are checked against EPA's source data directly.