Is Ray County, MO a radon risk area?

Ray County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Rank it against the rest of the country and Ray County lands in the 48th percentile for radon potential.

How Ray County compares

About 23,199 people live in Ray County, Missouri, spread over 568.979 square miles. That works out to roughly 41 people per square mile. Rank 575 by population within its EPA zone puts Ray County at the 44th percentile among zone peers. EPA's geology-based Region 7 groups Ray County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Ray County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Ray County — testing is the only way to know an individual home's actual level.

Testing and mitigation in Ray County

Nothing about Ray County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Missouri's state radon program

Ray County's test kit answers today; a Airthings radon monitor keeps answering for Ray County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Ray County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.