North Dakota Radon Levels
53Zone 1 (High)
0Zone 2 (Moderate)
0Zone 3 (Low)
100% of counties in North Dakota are classified as EPA Zone 1 (highest radon potential), meaning predicted average indoor radon levels exceed 4 pCi/L — the EPA action level. The EPA recommends that all homes be tested for radon, regardless of zone classification.
| County | EPA Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Barnes County | Zone 1 | Highest Potential |
| Benson County | Zone 1 | Highest Potential |
| Billings County | Zone 1 | Highest Potential |
| Bottineau County | Zone 1 | Highest Potential |
| Bowman County | Zone 1 | Highest Potential |
| Burke County | Zone 1 | Highest Potential |
| Burleigh County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Cavalier County | Zone 1 | Highest Potential |
| Dickey County | Zone 1 | Highest Potential |
| Divide County | Zone 1 | Highest Potential |
| Dunn County | Zone 1 | Highest Potential |
| Eddy County | Zone 1 | Highest Potential |
| Emmons County | Zone 1 | Highest Potential |
| Foster County | Zone 1 | Highest Potential |
| Golden Valley County | Zone 1 | Highest Potential |
| Grand Forks County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Griggs County | Zone 1 | Highest Potential |
| Hettinger County | Zone 1 | Highest Potential |
| Kidder County | Zone 1 | Highest Potential |
| LaMoure County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| McHenry County | Zone 1 | Highest Potential |
| McIntosh County | Zone 1 | Highest Potential |
| McKenzie County | Zone 1 | Highest Potential |
| McLean County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Morton County | Zone 1 | Highest Potential |
| Mountrail County | Zone 1 | Highest Potential |
| Nelson County | Zone 1 | Highest Potential |
| Oliver County | Zone 1 | Highest Potential |
| Pembina County | Zone 1 | Highest Potential |
| Pierce County | Zone 1 | Highest Potential |
| Ramsey County | Zone 1 | Highest Potential |
| Ransom County | Zone 1 | Highest Potential |
| Renville County | Zone 1 | Highest Potential |
| Richland County | Zone 1 | Highest Potential |
| Rolette County | Zone 1 | Highest Potential |
| Sargent County | Zone 1 | Highest Potential |
| Sheridan County | Zone 1 | Highest Potential |
| Sioux County | Zone 1 | Highest Potential |
| Slope County | Zone 1 | Highest Potential |
| Stark County | Zone 1 | Highest Potential |
| Steele County | Zone 1 | Highest Potential |
| Stutsman County | Zone 1 | Highest Potential |
| Towner County | Zone 1 | Highest Potential |
| Traill County | Zone 1 | Highest Potential |
| Walsh County | Zone 1 | Highest Potential |
| Ward County | Zone 1 | Highest Potential |
| Wells County | Zone 1 | Highest Potential |
| Williams County | Zone 1 | Highest Potential |