Is radon high in Washington County, Minnesota?

Low. The model predicts a long-term basement average of 1.9 pCi/L in Washington County (close to the US average of 1.8 and about 22% below the Minnesota average of 2.4). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 84 of 87 Minnesota counties.

Should I test for radon in Washington County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Washington County already range from 1.6 to 2.8 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 1 mean for Washington County?

Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.9 pCi/L does not line up with Zone 1, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.

How much does radon mitigation cost in Washington County?

A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Minnesota quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

Radon levels in Washington County, Minnesota

LowEPA Zone 1

Predicted long-term basement average of 1.9 pCi/L (model estimate) across 15 ZIP codes - close to the US average of 1.8, about 22% below the Minnesota average of 2.4. Ranked #84 of 87 Minnesota counties.

Test Washington County, MN once anyway - radon varies house to house

The predicted basement average here is 1.9 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.

Get a short-term test kit →Or track it with a continuous monitor

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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 Minnesota test results are shown separately and labeled as such. How the numbers work.

1.9 ± 0.06

pCi/L predicted basement mean (model SD)

1.5 ± 0.06

pCi/L predicted upstairs (above-ground) mean

1.6-2.8

range of ZIP-level basement predictions in the county

Measured tests in Washington County (Minnesota Dept. of Health, 2016-2025)

Actual results from voluntary home tests, separate from the model above. Measured averages usually run higher than the model because tests skew toward basements and worried homeowners.

Mean: 3.2 pCi/L
Median: 2.4 pCi/L
Tests ≥ 4 pCi/L: 27.9%
Tests per year: 1,519

Source: MN Public Health Data Access.

What this means for Washington

The typical Washington County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.6 to 2.8 pCi/L.

Note that the EPA classifies Washington County as Zone 1 while the newer model predicts 1.9 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Minnesota counties: Lake County (1.9), St. Louis County (1.8), Lake of the Woods County (2.0), Isanti County (2.0). The state's highest is Rock County at 4.7 pCi/L.

ZIP codes in Washington County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIP	Basement	Upstairs	Grade
55125	1.6 ± 0.07	1.2	Low
55082	2.1 ± 0.06	1.8	Moderate
55016	2.2 ± 0.06	1.8	Moderate
55128	1.7 ± 0.07	1.3	Low
55038	1.5 ± 0.06	1.4	Low
55129	1.7 ± 0.07	1.4	Low
55042	1.9 ± 0.06	1.6	Low
55115	1.8 ± 0.06	1.4	Low
55071	2.7 ± 0.07	1.7	Moderate
55043	2.6 ± 0.08	1.8	Moderate
55003	2.3 ± 0.06	1.6	Moderate
55055	2.1 ± 0.05	1.6	Moderate
55073	2.4 ± 0.06	1.9	Moderate
55001	2.8 ± 0.06	2.1	Moderate
55047	2.3 ± 0.08	1.7	Moderate

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

Washington County radon questions

Is radon high in Washington County, Minnesota?: Low. The model predicts a long-term basement average of 1.9 pCi/L in Washington County (close to the US average of 1.8 and about 22% below the Minnesota average of 2.4). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 84 of 87 Minnesota counties.
Should I test for radon in Washington County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Washington County already range from 1.6 to 2.8 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 1 mean for Washington County?: Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.9 pCi/L does not line up with Zone 1, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in Washington County?: A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Minnesota quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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