Griggs County, ND: EPA's radon zone, explained

EPA places Griggs 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. Griggs County sits at the 67th percentile nationally for radon potential — above 67 of every 100 rated counties.

How Griggs County compares

Griggs County, North Dakota is home to about 2,227 people across 708.685 square miles. That works out to roughly 3 people per square mile. By population, Griggs County is the 1021st largest of every county sharing its EPA zone — the 4th percentile by population within that zone. Griggs County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Griggs County

Where the national indoor average runs about 1.3 pCi/L, Griggs County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Griggs County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Griggs County

For a Griggs County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find North Dakota's state radon program

For Griggs County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Griggs County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

Where Griggs County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.