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

EPA's own radon map rates Clark County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 34th percentile for radon potential — Clark County outranks 34% of every county EPA has rated.

Where Clark County sits nationally

Clark County, Kansas is home to about 1,873 people across 974.638 square miles. That works out to roughly 2 people per square mile. By population, Clark County is the 1005th largest of every county sharing its EPA zone — the 3rd percentile by population within that zone. EPA's geology-based Region 7 groups Clark County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Clark County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Clark County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Clark County

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

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