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

EPA places McPherson County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. McPherson County sits at the 85th percentile nationally for radon potential — above 85 of every 100 rated counties.

How McPherson County compares

McPherson County, Kansas is home to about 30,334 people across 898.285 square miles. That works out to roughly 34 people per square mile. By population, McPherson County is the 466th largest of every county sharing its EPA zone — the 56th percentile by population within that zone. Geologically, McPherson County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

What this actually means for a house in McPherson County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line McPherson County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Some McPherson County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Next steps for a home in McPherson County

For a McPherson 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 McPherson County, an ongoing number beats a one-time test - a Airthings radon monitor tracks McPherson 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 McPherson County's figures come from

McPherson County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.