What EPA's radon map says about Ward County

EPA places Ward 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. Rank it against the rest of the country and Ward County lands in the 92nd percentile for radon potential.

Where Ward County sits nationally

About 68,427 people live in Ward County, North Dakota, spread over 2,013.029 square miles. Averaged across its land area, Ward County runs about 34 people per square mile. Among counties sharing Ward County's EPA zone, it outranks 77% of them by population. Ward County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Ward County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Ward County will test well under the action level, and EPA's guidance is to test regardless of zone.

If Ward County tests above the action level

Mitigation cost doesn't depend on Ward 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

Ward County's test kit answers today; a Airthings radon monitor keeps answering for Ward 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. Whatever zone Ward County carries, the zone explainer covers what it does and doesn't tell you about any one house.