What EPA's radon map says about Ford County

Ford County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Rank it against the rest of the country and Ford County lands in the 78th percentile for radon potential.

Ford County by the numbers

About 13,451 people live in Ford County, Illinois, spread over 485.597 square miles. Averaged across its land area, Ford County runs about 28 people per square mile. Among counties sharing Ford County's EPA zone, it outranks 34% of them by population. EPA's geology-based Region 5 groups Ford County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Ford County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Being in Zone 1 raises the odds Ford County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

If Ford County tests above the action level

Mitigation cost doesn't depend on Ford 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

Ford County's test kit answers today; a Airthings radon monitor keeps answering for Ford 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 Ford County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.