What EPA's radon map says about Cook County

EPA's own radon map rates Cook County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally that's the 12th percentile for radon potential — Cook County outranks 12% of every county EPA has rated.

How Cook County compares

About 17,984 people live in Cook County, Georgia, spread over 228.469 square miles. That works out to roughly 79 people per square mile. Among counties sharing Cook County's EPA zone, it outranks 36% of them by population. EPA's geology-based Region 4 groups Cook County with 735 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

At Zone 3, Cook County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. Even at Zone 3, Cook County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Next steps for a home in Cook County

Mitigation cost doesn't depend on Cook 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 Georgia's state radon program

Cook County's test kit answers today; a Airthings radon monitor keeps answering for Cook 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

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