Gray County, KS: EPA's radon zone, explained

EPA's own radon map rates Gray County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Gray County sits at the 71st percentile nationally for radon potential — above 71 of every 100 rated counties.

How Gray County compares

Gray County, Kansas is home to about 5,730 people across 868.867 square miles. Population density there runs about 7 people per square mile. By population, Gray County is the 896th largest of every county sharing its EPA zone — the 16th percentile by population within that zone. EPA's geology-based Region 7 groups Gray County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Gray County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Gray County specifically.

Next steps for a home in Gray County

For a Gray County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Kansas's state radon program

For Gray County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Gray County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Gray County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Gray County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.