Radon in Minnesota: radon map by county
EPA's Map of Radon Zones puts 68 of Minnesota's 87 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 19 in Zone 2 and 0 in Zone 3. Of 90,826 building tests that radon laboratories reported for 2008 to 2017, 42.8% were at or above EPA's 4 pCi/L action level, against 36.5% nationally (number 12 of 42 states with 1,000+ tests). The highest county share is Rock County (83.8% of 138 tests).
Radon by county in Minnesota
| County | EPA zone | Lab tests | Median | 4+ pCi/L |
|---|---|---|---|---|
| Aitkin County | Zone 2 | 166 | 2.5 | 30.5% |
| Anoka County | Zone 2 | 4,520 | 1.9 | 17.4% |
| Becker County | Zone 1 | 228 | 4.0 | 51.4% |
| Beltrami County | Zone 2 | 383 | 3.4 | 41.9% |
| Benton County | Zone 2 | 348 | 2.8 | 30.7% |
| Big Stone County | Zone 1 | 112 | 5.0 | 67% |
| Blue Earth County | Zone 1 | 1,171 | 5.6 | 64.8% |
| Brown County | Zone 1 | 881 | 6.7 | 73.7% |
| Carlton County | Zone 2 | 495 | 3.5 | 44.8% |
| Carver County | Zone 1 | 2,671 | 3.3 | 41.4% |
| Cass County | Zone 2 | 363 | 3.1 | 33.5% |
| Chippewa County | Zone 1 | 181 | 6.1 | 64.7% |
| Chisago County | Zone 2 | 665 | 2.6 | 31.9% |
| Clay County | Zone 1 | 334 | 5.6 | 61.5% |
| Clearwater County | Zone 2 | 65 | 4.0 | 50.5% |
| Cook County | Zone 2 | 102 | 3.2 | 40.4% |
| Cottonwood County | Zone 1 | 264 | 6.3 | 68.1% |
| Crow Wing County | Zone 2 | 816 | 2.4 | 27.9% |
| Dakota County | Zone 1 | 7,122 | 3.1 | 38.7% |
| Dodge County | Zone 1 | 365 | 5.4 | 63.3% |
| Douglas County | Zone 1 | 820 | 5.1 | 62.1% |
| Faribault County | Zone 1 | 223 | 5.3 | 65.3% |
| Fillmore County | Zone 1 | 753 | 6.1 | 64.1% |
| Freeborn County | Zone 1 | 544 | 6.2 | 69.1% |
| Goodhue County | Zone 1 | 718 | 4.5 | 56.1% |
| Grant County | Zone 1 | 93 | 5.6 | 63.7% |
| Hennepin County | Zone 1 | 24,906 | 3.3 | 40.3% |
| Houston County | Zone 1 | 649 | 5.1 | 59.6% |
| Hubbard County | Zone 1 | 193 | 3.6 | 46.1% |
| Isanti County | Zone 2 | 343 | 2.3 | 18.6% |
| Itasca County | Zone 2 | 702 | 2.8 | 34.5% |
| Jackson County | Zone 1 | 230 | 6.8 | 69.8% |
| Kanabec County | Zone 1 | 251 | 3.6 | 46.5% |
| Kandiyohi County | Zone 1 | 554 | 5.5 | 65.6% |
| Kittson County | Zone 1 | 15 | 2.2 | 30.4% |
| Koochiching County | Zone 2 | 108 | 1.6 | 24.3% |
| Lac qui Parle County | Zone 1 | 130 | 5.3 | 63.5% |
| Lake County | Zone 2 | 147 | 1.6 | 21.8% |
| Lake of the Woods County | Zone 2 | 6 | 2.5 | 14.3% |
| Le Sueur County | Zone 1 | 588 | 5.9 | 65.7% |
| Lincoln County | Zone 1 | 85 | 6.8 | 64.2% |
| Lyon County | Zone 1 | 415 | 5.3 | 64.3% |
| Mahnomen County | Zone 1 | 27 | 4.8 | 62.5% |
| Marshall County | Zone 1 | 73 | 5.4 | 55.6% |
| Martin County | Zone 1 | 276 | 5.2 | 64.9% |
| McLeod County | Zone 1 | 710 | 5.1 | 61.7% |
| Meeker County | Zone 1 | 472 | 4.4 | 55.9% |
| Mille Lacs County | Zone 2 | 220 | 2.5 | 27.7% |
| Morrison County | Zone 2 | 629 | 3.0 | 36.3% |
| Mower County | Zone 1 | 395 | 3.8 | 48.2% |
| Murray County | Zone 1 | 142 | 6.7 | 76.4% |
| Nicollet County | Zone 1 | 826 | 5.3 | 62.7% |
| Nobles County | Zone 1 | 171 | 7.0 | 70.4% |
| Norman County | Zone 1 | 114 | 4.8 | 58.4% |
| Olmsted County | Zone 1 | 1,841 | 4.6 | 55.9% |
| Otter Tail County | Zone 1 | 431 | 4.7 | 57% |
| Pennington County | Zone 1 | 93 | 4.1 | 52.3% |
| Pine County | Zone 2 | 187 | 2.3 | 24.2% |
| Pipestone County | Zone 1 | 238 | 5.8 | 71.4% |
| Polk County | Zone 1 | 311 | 6.7 | 70.8% |
| Pope County | Zone 1 | 511 | 3.9 | 49.2% |
| Ramsey County | Zone 1 | 6,744 | 2.7 | 30.5% |
| Red Lake County | Zone 1 | 22 | 2.7 | 33.3% |
| Redwood County | Zone 1 | 276 | 6.5 | 70.1% |
| Renville County | Zone 1 | 205 | 7.0 | 75.2% |
| Rice County | Zone 1 | 1,470 | 4.8 | 59.2% |
| Rock County | Zone 1 | 138 | 7.7 | 83.8% |
| Roseau County | Zone 1 | 36 | 3.0 | 29.2% |
| Scott County | Zone 1 | 2,869 | 3.7 | 46.9% |
| Sherburne County | Zone 1 | 1,516 | 3.1 | 37.7% |
| Sibley County | Zone 1 | 297 | 5.5 | 66.6% |
| St. Louis County | Zone 2 | 3,010 | 2.0 | 23.7% |
| Stearns County | Zone 1 | 1,668 | 4.0 | 50.2% |
| Steele County | Zone 1 | 800 | 5.2 | 63.8% |
| Stevens County | Zone 1 | 210 | 5.2 | 63% |
| Swift County | Zone 1 | 178 | 4.3 | 53% |
| Todd County | Zone 1 | 171 | 3.7 | 48.4% |
| Traverse County | Zone 1 | 46 | 4.8 | 56.5% |
| Wabasha County | Zone 1 | 424 | 5.2 | 62.6% |
| Wadena County | Zone 1 | 101 | 3.1 | 37.2% |
| Waseca County | Zone 1 | 367 | 5.9 | 64.5% |
| Washington County | Zone 1 | 4,469 | 2.7 | 31.5% |
| Watonwan County | Zone 1 | 188 | 5.3 | 62.7% |
| Wilkin County | Zone 1 | 64 | 3.3 | 41.8% |
| Winona County | Zone 1 | 1,440 | 4.0 | 50% |
| Wright County | Zone 1 | 2,581 | 4.1 | 52.2% |
| Yellow Medicine County | Zone 1 | 144 | 6.0 | 71.6% |
Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).
What the zones mean
Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.
Radon in Minnesota: questions
What radon zone is Minnesota?
EPA's 1993 map does not give states one zone; it zones each county. In Minnesota, 68 counties are Zone 1, 19 Zone 2 and 0 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".
Which Minnesota counties have the highest radon levels?
By the share of laboratory tests at or above 4 pCi/L for 2008 to 2017 (counties with 20 or more tests): Rock County 83.8% (median 7.7 pCi/L, 138 tests); Murray County 76.4% (median 6.7 pCi/L, 142 tests); Renville County 75.2% (median 7.0 pCi/L, 205 tests); Brown County 73.7% (median 6.7 pCi/L, 881 tests); Yellow Medicine County 71.6% (median 6.0 pCi/L, 144 tests).
How common is high radon in Minnesota?
42.8% of the 90,826 tests in the laboratory data for Minnesota (2008 to 2017) were at or above 4 pCi/L; the national share was 36.5%. Buildings are tested by choice, often because of a sale or a concern, so the share describes the tests on file, not every home.
Does Minnesota publish its own radon test data?
Minnesota's radon program reports county test results; the latest year with county results is 2023, shown on each county page.
Should I test for radon in Minnesota?
Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.
States bordering Minnesota
Other free hazard lookups
- Radon by county and ZIP codeEPA radon zone and the radon test results on file for any county, ZIP code or address.
- Fault lines near an addressUSGS-mapped earthquake faults within 5 miles, their age and slip rate, and the USGS seismic hazard value.
- Power lines near an addressHigh-voltage transmission lines within 1 mile from federal maps, with voltage and distance.
- Flood zone lookupThe FEMA flood zone mapped at any US address. Not an official flood zone determination.
- Superfund sites near an addressThe nearest EPA Superfund (NPL) sites and their status.
All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).
Superfund sites in Minnesota · Radon map of every state
Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.