What EPA's radon map says about Rock County

Rock County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally that's the 1st percentile for radon potential — Rock County outranks 1% of every county EPA has rated.

Where Rock County sits nationally

About 1,241 people live in Rock County, Nebraska, spread over 1,008.291 square miles. Population density there runs about 1 people per square mile. Among counties sharing Rock County's EPA zone, it outranks 2% of them by population. Rock County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Rock County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. A Zone 3 label describes Rock County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

If Rock County tests above the action level

Mitigation cost doesn't depend on Rock 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 Nebraska's state radon program

Rock County's test kit answers today; a Airthings radon monitor keeps answering for Rock 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 Rock County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.