What EPA's radon map says about Sargent County

EPA's own radon map rates Sargent County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Sargent County sits at the 69th percentile nationally for radon potential — above 69 of every 100 rated counties.

Sargent County by the numbers

About 3,710 people live in Sargent County, North Dakota, spread over 858.491 square miles. Population density there runs about 4 people per square mile. Among counties sharing Sargent County's EPA zone, it outranks 10% of them by population. Sargent 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

Sargent County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Being in Zone 1 raises the odds Sargent 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 Sargent County tests above the action level

Mitigation cost doesn't depend on Sargent 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

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