Radon levels in Duluth, Minnesota
LowEPA Zone 2Predicted long-term basement average of 1.8 pCi/L (model estimate) across the 10 modeled ZIP codes in Duluth - close to the US average of 1.8, about 26% below the Minnesota average of 2.4. Ranked #21 of 23 Minnesota cities on this site. Most of the city lies in St. Louis County.
Test Duluth, MN once anyway - radon varies house to house
The predicted basement average here is 1.8 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.
We may earn a commission from Amazon at no extra cost to you.
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. Measured state test results are shown separately below, labeled with their source and years. How the numbers work.
1.8 ± 0.07
pCi/L predicted basement mean (model SD)
1.0 ± 0.08
pCi/L predicted upstairs (above-ground) mean
1.1-2.3
range of ZIP-level basement predictions in the city
0%
of Duluth ZIPs predicted ≥ 4 pCi/L (20% ≥ 2)
Measured radon tests in St. Louis County (Minnesota Department of Health (MN Public Health Data Access), 2016-2025)
Actual results from home radon tests reported to the state, separate from the model estimate above. Coverage: 2016-2025.
- Measured mean
- 3.3 pCi/L
- Measured median
- 2.2 pCi/L
- Results ≥ 4 pCi/L
- 26.6%
- Results ≥ 2 pCi/L
- 56.4%
- Sample
- about 602 properties tested per year
| Figure | Model (predicted) | State tests (measured) |
|---|---|---|
| Mean, pCi/L | 1.8 basement | 3.3 |
| Share ≥ 4 pCi/L | not a model output | 26.6% |
The measured mean runs 1.5 pCi/L above the model because state test data is voluntary and skews toward basements, winter, and homeowners who already suspected a problem, while the model estimates the long-term average across all homes.
Source: Minnesota radon test results by county, Minnesota Department of Health (MN Public Health Data Access). Minnesota public data (Minn. Stat. ch. 13). Method and download.
What this means for Duluth
The typical Duluth home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.1 to 2.3 pCi/L.
The city figure is not a separate estimate: it is the mean of the model's ZIP-code predictions, weighted by the share of the city's land in each ZIP (Census 2020 ZCTA-to-place relationship file). Note that the EPA classifies St. Louis County as Zone 2 while the newer model predicts 1.8 pCi/L for Duluth; where they disagree, we grade on the model but show both.
Comparable Minnesota cities: Eagan (1.8), Lakeville (1.9), Maple Grove (1.9), Coon Rapids (1.9).
ZIP codes in Duluth
ZIPs that overlap the city, largest share of its land first. Predicted basement and upstairs means are model estimates; ZIPs the model does not cover show a dash.
| ZIP | Share of city | Basement | Upstairs | Grade |
|---|---|---|---|---|
| 55811 | 26% | 2.1 ± 0.06 | 1.1 | Moderate |
| 55808 | 17% | 1.7 ± 0.07 | 0.9 | Low |
| 55804 | 14% | 1.8 ± 0.06 | 0.9 | Low |
| 55803 | 13% | 2.3 ± 0.07 | 1.1 | Moderate |
| 55810 | 9% | 1.6 ± 0.07 | 1.2 | Low |
| 55807 | 8% | 1.4 ± 0.07 | 0.8 | Low |
| 55806 | 5% | 1.2 ± 0.08 | 0.7 | Low |
| 55802 | 4% | 1.5 ± 0.12 | 0.9 | Low |
| 55812 | 3% | 1.5 ± 0.06 | 0.9 | Low |
| 55805 | 2% | 1.1 ± 0.10 | 0.7 | Low |
Testing help in Minnesota
Minnesota's radon program page is at www.health.state.mn.us; it lists testing and certified-mitigator guidance. EPA state radon contacts page. If a test comes back at 4 pCi/L or higher, mitigation typically costs $800-$2,500 installed; use EPA find-a-professional and read the mitigation guide.
Duluth radon questions
- Is radon high in Duluth, Minnesota?
- Low. Averaging the model's ZIP-code predictions across Duluth (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.8 pCi/L - close to the US average of 1.8 and about 26% below the Minnesota average of 2.4. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Duluth ranks 21 of 23 Minnesota cities on this site.
- What do actual radon tests show around Duluth?
- Minnesota Department of Health (MN Public Health Data Access) publishes results for St. Louis County (not the city alone) covering 2016-2025 (about 602 properties tested per year): an average of 3.3 pCi/L, a median of 2.2, 26.6% of results at or above the 4 pCi/L action level. These are voluntary home tests, so they skew toward basements and toward homes where radon was suspected; the model's predicted basement average for Duluth is 1.8 pCi/L.
- Which Duluth ZIP codes have the highest radon?
- Predictions for the 10 modeled ZIP codes in Duluth range from 1.1 to 2.3 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 20% at or above 2. That spread is why the ZIP table below matters more than the city-wide number.
- Should I test for radon in Duluth?
- Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Duluth's low predicted average describes the typical home, not yours.
- What does EPA Radon Zone 2 mean for Duluth?
- Duluth sits mainly in St. Louis County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The newer model's city average of 1.8 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
← All Minnesota counties and cities · St. Louis County · How to test · Methodology