Is Sumner County, KS a radon risk area?

EPA places Sumner County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Sumner County ranks higher in radon potential than 47% of rated counties (the 47th percentile).

How Sumner County compares

About 22,336 people live in Sumner County, Kansas, spread over 1,181.668 square miles. Averaged across its land area, Sumner County runs about 19 people per square mile. Rank 590 by population within its EPA zone puts Sumner County at the 43rd percentile among zone peers. EPA's geology-based Region 7 groups Sumner County with 411 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Sumner County's Zone 2 prediction lands in the gap between the two. A county-wide moderate average, like Sumner County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Sumner County

Nothing about Sumner 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 Kansas's state radon program

Sumner County's test kit answers today; a Airthings radon monitor keeps answering for Sumner 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 Sumner County's numbers. Whatever zone Sumner County carries, the zone explainer covers what it does and doesn't tell you about any one house.