What EPA's radon map says about Eddy County

EPA places Eddy County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Eddy County in the 68th percentile nationally for radon potential — higher than 68% of the counties EPA has rated.

Where Eddy County sits nationally

About 2,309 people live in Eddy County, North Dakota, spread over 630.239 square miles. Averaged across its land area, Eddy County runs about 4 people per square mile. Among counties sharing Eddy County's EPA zone, it outranks 5% of them by population. Eddy County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Eddy County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. That doesn't mean every Eddy County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

Testing and mitigation in Eddy County

Mitigation cost doesn't depend on Eddy 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 North Dakota's state radon program

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