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

Phillips County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 70th percentile for radon potential — Phillips County outranks 70% of every county EPA has rated.

Where Phillips County sits nationally

Phillips County, Kansas is home to about 4,733 people across 885.871 square miles. That works out to roughly 5 people per square mile. By population, Phillips County is the 931st largest of every county sharing its EPA zone — the 13th percentile by population within that zone. Phillips County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Phillips County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Phillips County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Being in Zone 1 raises the odds Phillips County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Next steps for a home in Phillips County

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

Where Phillips County's figures come from

Phillips County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Phillips County carries, the zone explainer covers what it does and doesn't tell you about any one house.