What EPA's radon map says about Kane County

Kane County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Kane County in the 99th percentile nationally for radon potential — higher than 99% of the counties EPA has rated.

How Kane County compares

About 520,997 people live in Kane County, Illinois, spread over 519.361 square miles. Averaged across its land area, Kane County runs about 1,003 people per square mile. Among counties sharing Kane County's EPA zone, it outranks 96% of them by population. Geologically, Kane County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

What this actually means for a house in Kane County

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Kane County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Kane County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Kane County

Mitigation cost doesn't depend on Kane County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Illinois's state radon program

Kane County's test kit answers today; a Airthings radon monitor keeps answering for Kane County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

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