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

EPA's own radon map rates Shawnee County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 62nd percentile for radon potential — Shawnee County outranks 62% of every county EPA has rated.

Shawnee County by the numbers

Shawnee County, Kansas is home to about 177,942 people across 544.012 square miles. That works out to roughly 327 people per square mile. By population, Shawnee County is the 132nd largest of every county sharing its EPA zone — the 87th percentile by population within that zone. EPA's geology-based Region 7 groups Shawnee County with 411 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Shawnee County

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Shawnee County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Shawnee County address — a moderate county average still leaves individual homes to test either side of it.

If Shawnee County tests above the action level

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

Where Shawnee County's figures come from

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