Highest result per tested property in Marshall County
| Result | Share | EPA guidance |
|---|---|---|
| Below 2 pCi/L | 24% | Below EPA's levels |
| 2 to 4 pCi/L | 30% | Consider fixing |
| 4 pCi/L or more | 46% | EPA recommends fixing |
What the data shows
- Higher share of high results than 38 of 87 Minnesota counties.
- Higher than 3 of 5 neighbouring counties.
- 76% of results at or above 2 pCi/L.
- 1 in 20 results above 21.1 pCi/L.
- Median result 3.8 pCi/L: between the 2 and 4 pCi/L EPA levels.
How Marshall County compares
Data table
| Area | Properties ≥ 4 pCi/L |
|---|---|
| Polk County | 70% |
| Pennington County | 56% |
| Marshall County | 46% |
| Beltrami County | 39% |
| Roseau County | 30% |
| Kittson County | 28% |
Same source as Marshall County. Other bordering counties: Grand Forks County, North Dakota, Pembina County, North Dakota, Walsh County, North Dakota.
What it means for your home
About 1 in 2 results in Marshall County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.
Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.
Test your home
Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide
Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.
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Fixing high radon
No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →
Minnesota licenses radon mitigators. Source
Buying or selling here
Minnesota's Radon Awareness Act requires sellers to disclose in writing any known radon tests, results and mitigation, and to give buyers the Department of Health publication "Radon in Real Estate Transactions" (Minn. Stat. § 144.496). Source
Checked against the official text on 2026-11-03. Not legal advice.
About this data
Source: Minnesota county radon testing indicators (Minnesota Department of Health). Period: 2016–2025. Published indicators: 57 properties at or above 4 pCi/L, 94 at or above 2 pCi/L, and 12 properties tested annually on average. Read the methodology →
These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.
About this page
Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us