Is Lake County, IL a radon risk area?

EPA's own radon map rates Lake County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, Lake County ranks higher in radon potential than 65% of rated counties (the 65th percentile).

Lake County by the numbers

About 718,604 people live in Lake County, Illinois, spread over 443.68 square miles. Averaged across its land area, Lake County runs about 1,620 people per square mile. Rank 33 by population within its EPA zone puts Lake County at the 97th percentile among zone peers. Geologically, Lake 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 Lake County

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 Lake County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Lake County — testing is the only way to know an individual home's actual level.

Next steps for a home in Lake County

Nothing about Lake County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Illinois's state radon program

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

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.