Radon levels in North Dakota: Moderate
The model predicts a population-weighted basement average of 3.3 pCi/L (model estimate) across North Dakota's 53 counties - about 1.8× the US average of 1.8 pCi/L. Above-ground floors average 2.1 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
53 / 53
EPA Zone 1 counties (100%)
0 / 0
Zone 2 / Zone 3 counties
11
counties predicted ≥ 4 pCi/L
11.7%
of ZIP codes predicted ≥ 4 pCi/L
Test North Dakota - the EPA says "consider fixing" in this range
The predicted basement average here is 3.3 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.
Monitor link goes to the Airthings store - use code RADONGRADE-10OFF at checkout for 10% off any Airthings monitor.
Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.
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What the data says about radon in North Dakota
53 of North Dakota's 53 counties are EPA Zone 1 (100%), 0 are Zone 2 and 0 are Zone 3 on the EPA's county-level map. Every county in the state is in the highest-potential zone, which the EPA defines as a predicted average indoor screening level above 4 pCi/L. The zones were drawn once, from geology and the tests available in 1993, and the EPA itself notes that homes with elevated radon exist in all three zones.
Weighted by where people live, North Dakota's predicted basement average is 3.3 pCi/L - 1.8× the US population-weighted average of 1.8 - which puts the state in the moderate range. Of the 53 counties with predictions, 11 are predicted at or above 4 pCi/L, 42 in the 2-4 band and 0 below 2. The highest predicted county is Grand Forks County at 4.4 pCi/L; the lowest is Ward County at 2.5 - a 1.8 pCi/L spread that means a statewide average tells you little about any one county.
Nationally 4.2% of ZIPs are predicted at 4+ pCi/L and 48.7% at 2+; in North Dakota it is 11.7% and 99.7% - above the national figures on both counts. With more than half of ZIPs above 2, a test is worth doing before any purchase or renovation here.
North Dakota counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 53 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Grand Forks County | 4.4 pCi/L | 2.4 | High | EPA Zone 1 | 14 |
| Ransom County | 4.2 pCi/L | 2.5 | High | EPA Zone 1 | 4 |
| Walsh County | 4.2 pCi/L | 2.6 | High | EPA Zone 1 | 11 |
| Foster County | 4.2 pCi/L | 2.4 | High | EPA Zone 1 | 3 |
| Ramsey County | 4.1 pCi/L | 2.4 | High | EPA Zone 1 | 10 |
| Emmons County | 4.1 pCi/L | 2.4 | High | EPA Zone 1 | 7 |
| Griggs County | 4.1 pCi/L | 2.3 | High | EPA Zone 1 | 4 |
| LaMoure County | 4.1 pCi/L | 2.3 | High | EPA Zone 1 | 7 |
| Steele County | 4.0 pCi/L | 2.4 | High | EPA Zone 1 | 6 |
| Stutsman County | 4.0 pCi/L | 2.2 | High | EPA Zone 1 | 11 |
| Eddy County | 4.0 pCi/L | 2.4 | High | EPA Zone 1 | 4 |
| Barnes County | 4.0 pCi/L | 2.2 | Moderate | EPA Zone 1 | 10 |
| Billings County | 3.9 pCi/L | 2.2 | Moderate | EPA Zone 1 | 3 |
| Towner County | 3.9 pCi/L | 2.4 | Moderate | EPA Zone 1 | 7 |
| Traill County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 9 |
| McIntosh County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 3 |
| Benson County | 3.8 pCi/L | 2.2 | Moderate | EPA Zone 1 | 8 |
| Nelson County | 3.8 pCi/L | 2.2 | Moderate | EPA Zone 1 | 8 |
| Pierce County | 3.8 pCi/L | 2.2 | Moderate | EPA Zone 1 | 2 |
| Pembina County | 3.8 pCi/L | 2.3 | Moderate | EPA Zone 1 | 11 |
| Dickey County | 3.8 pCi/L | 2.1 | Moderate | EPA Zone 1 | 5 |
| Cavalier County | 3.8 pCi/L | 2.3 | Moderate | EPA Zone 1 | 8 |
| Bottineau County | 3.7 pCi/L | 2.3 | Moderate | EPA Zone 1 | 9 |
| Sargent County | 3.7 pCi/L | 2.2 | Moderate | EPA Zone 1 | 8 |
| McHenry County | 3.7 pCi/L | 2.3 | Moderate | EPA Zone 1 | 12 |
| Oliver County | 3.7 pCi/L | 2.5 | Moderate | EPA Zone 1 | 1 |
| Sheridan County | 3.7 pCi/L | 2.2 | Moderate | EPA Zone 1 | 4 |
| Stark County | 3.6 pCi/L | 2.1 | Moderate | EPA Zone 1 | 6 |
| McLean County | 3.6 pCi/L | 2.3 | Moderate | EPA Zone 1 | 13 |
| Wells County | 3.6 pCi/L | 2.3 | Moderate | EPA Zone 1 | 7 |
| Adams County | 3.5 pCi/L | 2.1 | Moderate | EPA Zone 1 | 2 |
| Grant County | 3.5 pCi/L | 2.1 | Moderate | EPA Zone 1 | 5 |
| Renville County | 3.5 pCi/L | 2.2 | Moderate | EPA Zone 1 | 5 |
| Kidder County | 3.5 pCi/L | 2.1 | Moderate | EPA Zone 1 | 6 |
| Logan County | 3.5 pCi/L | 2.0 | Moderate | EPA Zone 1 | 4 |
| Richland County | 3.5 pCi/L | 2.1 | Moderate | EPA Zone 1 | 12 |
| Rolette County | 3.5 pCi/L | 2.0 | Moderate | EPA Zone 1 | 6 |
| Slope County | 3.5 pCi/L | 2.2 | Moderate | EPA Zone 1 | 2 |
| Mercer County | 3.4 pCi/L | 2.2 | Moderate | EPA Zone 1 | 5 |
| Hettinger County | 3.4 pCi/L | 2.2 | Moderate | EPA Zone 1 | 2 |
| Burke County | 3.4 pCi/L | 2.2 | Moderate | EPA Zone 1 | 6 |
| Morton County | 3.3 pCi/L | 2.1 | Moderate | EPA Zone 1 | 8 |
| Mountrail County | 3.3 pCi/L | 2.0 | Moderate | EPA Zone 1 | 7 |
| Dunn County | 3.2 pCi/L | 2.0 | Moderate | EPA Zone 1 | 6 |
| Sioux County | 3.2 pCi/L | 1.9 | Moderate | EPA Zone 1 | 3 |
| Bowman County | 3.2 pCi/L | 2.1 | Moderate | EPA Zone 1 | 4 |
| Golden Valley County | 3.2 pCi/L | 2.2 | Moderate | EPA Zone 1 | 3 |
| Divide County | 3.2 pCi/L | 2.1 | Moderate | EPA Zone 1 | 5 |
| McKenzie County | 3.0 pCi/L | 2.0 | Moderate | EPA Zone 1 | 6 |
| Burleigh County | 2.9 pCi/L | 2.0 | Moderate | EPA Zone 1 | 11 |
| Cass County | 2.8 pCi/L | 2.0 | Moderate | EPA Zone 1 | 23 |
| Williams County | 2.6 pCi/L | 1.9 | Moderate | EPA Zone 1 | 9 |
| Ward County | 2.5 pCi/L | 2.0 | Moderate | EPA Zone 1 | 11 |
Radon levels in North Dakota cities
The 4 most-populous North Dakota places among the 1,000 largest US cities (Census incorporated places and CDPs), by population. City figures are ZIP-land-weighted means of the model's ZIP predictions (model estimate).
| City | Population | Predicted basement | Upstairs | Grade | ZIPs ≥ 4 |
|---|---|---|---|---|---|
| Fargo | 133,188 | 2.8 pCi/L | 2.0 | Moderate | 0% |
| Bismarck | 75,092 | 2.8 pCi/L | 2.0 | Moderate | 0% |
| Grand Forks | 58,921 | 4.4 pCi/L | 2.4 | High | 100% |
| Minot | 47,373 | 2.5 pCi/L | 1.9 | Moderate | 0% |
Highest-radon ZIP codes in North Dakota
The 10 North Dakota ZIP codes with the highest predicted basement average (model estimate), out of 366 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 58012 | Cass County | 4.8 pCi/L | 2.8 | High |
| 58201 | Grand Forks County | 4.7 pCi/L | 2.5 | High |
| 58054 | Ransom County | 4.6 pCi/L | 2.6 | High |
| 58251 | Grand Forks County | 4.5 pCi/L | 2.4 | High |
| 58261 | Walsh County | 4.4 pCi/L | 2.5 | High |
| 58425 | Griggs County | 4.4 pCi/L | 2.4 | High |
| 58267 | Grand Forks County | 4.3 pCi/L | 2.6 | High |
| 58237 | Walsh County | 4.3 pCi/L | 2.9 | High |
| 58009 | Traill County | 4.3 pCi/L | 2.3 | High |
| 58552 | Emmons County | 4.3 pCi/L | 2.5 | High |
North Dakota radon questions
- Is radon high in North Dakota?
- North Dakota's population-weighted predicted basement average is 3.3 pCi/L, about 1.8× the US average of 1.8. 11 of its 53 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 42 are in the 2-4 "consider fixing" range and 0 are below 2. 11.7% of North Dakota ZIP codes are predicted at 4 or higher.
- Which North Dakota county has the highest radon?
- Grand Forks County has the highest predicted basement average in North Dakota at 4.4 pCi/L (EPA Zone 1). The lowest is Ward County at 2.5 pCi/L. These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in North Dakota?
- 53 of North Dakota's 53 counties (100%) are EPA Zone 1 (highest potential), 0 are Zone 2 and 0 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in North Dakota?
- Yes - with some urgency. North Dakota's predicted average is in the moderate range, and 99.7% of its ZIP codes are predicted at 2 pCi/L or higher. A short-term charcoal kit or a continuous digital monitor will tell you your actual level within days.
North Dakota radon program
North Dakota's radon program page is at deq.nd.gov; it lists testing and certified-mitigator guidance for the state. The EPA also keeps a directory of every state radon contact: EPA state radon contacts page. Then read how to test and what mitigation costs.