Minnesota · county radon data
Radon in Hennepin County, Minnesota
40.3% of the 24,906 home radon tests on record here reached the EPA action level — mid-pack for the state, ranked #64 of 87 tested Minnesota counties.
What the numbers say
Hennepin County sits 15.6 points below the Minnesota median (55.9% of tests over the limit across the state's counties). The median reading among its 24,906 reported tests was 3.3 pCi/L — and the single highest test on record reached 195.9 pCi/L, more than 48× the action level. EPA maps place the county in Radon Zone 1 — its highest-potential category, where average indoor screening levels are predicted above 4 pCi/L.
Why: the ground under Hennepin County
Blanketed by clay-rich glacial till carrying ground-up uranium-bearing rock — the geologic reason nearly all of Minnesota is EPA Zone 1 and the state's average indoor radon runs roughly triple the national average. Long heating seasons in tight houses compound what the ground supplies.
Geology sources: MN Dept of Health · USGS WRI 98-4169.
The housing stock factor
The median Hennepin County home dates to 1973 — decades before radon-resistant new construction entered building codes. With 1,269,496 residents largely housed in that older stock, testing is the only way any individual household knows where it stands.
ZIP codes in Hennepin County
Minnesota doesn't publish ZIP-level test results, so these ZIPs share the county figures above — the roster is here so you can confirm your address is covered by this data.
| ZIP | Place |
|---|---|
| 55111 | Saint Paul |
| 55305 | Hopkins |
| 55311 | Maple Grove |
| 55316 | Champlin |
| 55327 | Dayton |
| 55331 | Excelsior |
| 55340 | Hamel |
| 55343 | Hopkins |
| 55344 | Eden Prairie |
| 55345 | Minnetonka |
| 55346 | Eden Prairie |
| 55347 | Eden Prairie |
| 55356 | Long Lake |
| 55357 | Loretto |
| 55359 | Maple Plain |
| 55364 | Mound |
| 55369 | Osseo |
| 55373 | Rockford |
| 55374 | Rogers |
| 55375 | Saint Bonifacius |
| 55384 | Spring Park |
| 55391 | Wayzata |
| 55401 | Minneapolis |
| 55402 | Minneapolis |
| 55403 | Minneapolis |
| 55404 | Minneapolis |
| 55405 | Minneapolis |
| 55406 | Minneapolis |
| 55407 | Minneapolis |
| 55408 | Minneapolis |
| 55409 | Minneapolis |
| 55410 | Minneapolis |
| 55411 | Minneapolis |
| 55412 | Minneapolis |
| 55413 | Minneapolis |
| 55414 | Minneapolis |
| 55415 | Minneapolis |
| 55416 | Minneapolis |
| 55417 | Minneapolis |
| 55418 | Minneapolis |
| 55419 | Minneapolis |
| 55420 | Minneapolis |
| 55422 | Minneapolis |
| 55423 | Minneapolis |
| 55424 | Minneapolis |
| 55425 | Minneapolis |
| 55426 | Minneapolis |
| 55427 | Minneapolis |
| 55428 | Minneapolis |
| 55429 | Minneapolis |
| 55430 | Minneapolis |
| 55431 | Minneapolis |
| 55435 | Minneapolis |
| 55436 | Minneapolis |
| 55437 | Minneapolis |
| 55438 | Minneapolis |
| 55439 | Minneapolis |
| 55441 | Minneapolis |
| 55442 | Minneapolis |
| 55443 | Minneapolis |
+7 more — look yours up in the ZIP tool.
Hennepin County in the Minnesota picture
| Hennepin County | 40.3% over the limit | 24,906 tests |
| Minnesota's highest: Rock County | 83.8% | 138 tests |
| Minnesota county median | 55.9% | 87 counties ranked |
| Share of all Minnesota tests from this county | 27.4% | |
Ranked nearby in Minnesota
- Wilkin County — #61, 41.8% of 64 tests over the limit
- Carver County — #62, 41.4% of 2,671 tests over the limit
- Cook County — #63, 40.4% of 102 tests over the limit
- Dakota County — #65, 38.7% of 7,122 tests over the limit
- Sherburne County — #66, 37.7% of 1,516 tests over the limit
- Wadena County — #67, 37.2% of 101 tests over the limit
(Ranking neighbors — counties adjacent in the Minnesota test ranking, not necessarily on the map.)
High test? Fixes and real pricing: the Minnesota mitigation cost guide. Every statistic here traces to the methodology (CDC EPHT (labs), 2008–2017; zones: EPA; year built & population: ACS 5-year).
Hennepin County radon FAQ
- Is radon high in Hennepin County?
- 40.3% of 24,906 home tests reported to the CDC came back at or above the EPA action level of 4 pCi/L — 15.6 points below the Minnesota county median of 55.9%, ranking #64 of 87 tested counties. EPA classifies the county as Zone 1.
- Does an older home in Hennepin County mean more radon risk?
- The county's median home was built in 1973 — before radon-resistant construction practices entered building codes in the 1990s, so most of the housing stock has no built-in radon protection. Construction age changes the odds, not the answer: only a test tells you about your house.
- Where do these Hennepin County numbers come from?
- 24,906 aggregated home tests in the CDC's Environmental Public Health Tracking dataset (CDC EPHT 2008-2017). Median reading: 3.3 pCi/L; the highest recorded test hit 195.9 pCi/L. How we handle the data, including its limits, is documented on our methodology page.
- What's the highest radon reading recorded in Hennepin County?
- 195.9 pCi/L — 48× the EPA action level — against a county median of 3.3 pCi/L across 24,906 tests. That spread is the point: neighboring homes routinely test wildly differently.