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

EPA's own radon map rates Franklin County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Franklin County sits at the 49th percentile nationally for radon potential — above 49 of every 100 rated counties.

Where Franklin County sits nationally

Franklin County, Kansas is home to about 26,273 people across 571.772 square miles. That works out to roughly 46 people per square mile. By population, Franklin County is the 530th largest of every county sharing its EPA zone — the 49th percentile by population within that zone. EPA's geology-based Region 7 groups Franklin County with 411 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Franklin County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A county-wide moderate average, like Franklin County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Franklin County

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

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