Clark County, WI radon potential

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. Clark County sits at the 52nd percentile nationally for radon potential — above 52 of every 100 rated counties.

Clark County by the numbers

Clark County, Wisconsin is home to about 34,801 people across 1,209.698 square miles. Population density there runs about 29 people per square mile. Within its own EPA zone, Clark County is bigger by population than 57% of the counties that share it. Geologically, Clark County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

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 Clark County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Clark County address — a moderate county average still leaves individual homes to test either side of it.

Testing and mitigation in Clark County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Wisconsin'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.