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Radon Levels in Blue Earth County, Minnesota

EPA puts Blue Earth County in Zone 1, its highest radon zone, and 32.7% of its 392 reported radon tests (2023) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    32.7%

    1.9 pts below MN

    Blue Earth
    32.7%
    Minnesota
    34.6%

    392 tests, 2023

  • Median result

    2.2pCi/L

    Below action level

    Blue Earth
    2.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    392

    11th of 62 by tests

    Blue Earth
    392
    Hennepin
    6,545

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Minnesota

    48 of 62

    Lowest quarter

    Blue Earth
    32.7%
    Renville
    75.7%

    By share, of 62 with 30+ tests

Read a result for Blue Earth County

Starts at Blue Earth County's median, 2.2 pCi/L

2.2pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 2.2 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Blue Earth County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Blue Earth County, At a glance

Blue Earth County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Blue Earth County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Blue Earth County, 2023

Share of reported tests at or above 4 pCi/L, by year, Blue Earth County
Share of reported tests at or above 4 pCi/L, by year, Blue Earth County
YearShare of reported tests at or above 4 pCi/L
201465.0%
201562.5%
201658.9%
201758.6%
201852.3%
201953.6%
202042.8%
202134.4%
202232.3%
202332.7%

2023: 32.7%. Across these years the share ran from 32.3% to 65.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 392 tests reported to CDC for Blue Earth County over 2023, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Blue Earth County, Compared

Blue Earth County radon figures, compared

Calculated by Radon411

In Blue Earth County, about 3 in 10 reported tests in 2023 (128 of 392) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 0.7 points lower. Across 86 Minnesota counties pooled together, 34.6% of tests reached that level, so Blue Earth County runs 1.9 points below its state.

Of 6 neighbours with a figure, all 6 reported a larger share at or above 4 pCi/L; the spread is 43.2% (Martin County) to 70.0% (Faribault County). By share, Blue Earth County is 48th of 62 Minnesota counties with 30 or more tests for the same period.

Year by year, 2014 opened at 65.0% and 2023 closed at 32.7% (down 32.3 points), with 2014 the high at 65.0%. Half the tests came in under 2.2 pCi/L and half over it; the single highest reached 94.4 pCi/L. Below the action level, 181 tests (46.2%) came in under 2 pCi/L, against 36.6% statewide, and 83 tests (21.2%) fell between 2 and 4, against 28.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 32.7% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

The busiest year on file was 2021, with 532 tests reported; the quietest, 2019, had 207.

Share of reported tests at or above 4 pCi/L by year, Blue Earth County against Minnesota2014 to 2023, years with 30 or more tests: Blue Earth County 65.0% to 32.7%, the state's pooled share 34.6% in 2023.
Blue Earth CountyMinnesota, pooled
Share of reported tests at or above 4 pCi/L by year, Blue Earth County against Minnesota: data table
YearTestsBlue Earth County, at or above 4 pCi/LMinnesota, pooled
201443265.0%42.9%
201537662.5%43.6%
201641858.9%37.0%
201729758.6%38.2%
201828752.3%38.3%
201920753.6%36.1%
202025742.8%31.8%
202153234.4%33.1%
202249332.3%31.6%
202339232.7%34.6%
Blue Earth County against Minnesota, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Blue Earth County
Blue Earth County39232.7%2.2 pCi/LThis county
Minnesota, pooled86 counties, pooled22,44934.6%Not pooled+1.9 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+0.7 points
Renville Countyhighest in the state3775.7%6.3 pCi/L+43.0 points
Lake Countylowest in the state783.8%1.3 pCi/L−28.9 points
Faribault County, MNborders it3070.0%8.1 pCi/L+37.3 points
Watonwan County, MNborders it2466.7%6.2 pCi/L+34.0 points
Brown County, MNborders it11563.5%5.4 pCi/L+30.8 points
Le Sueur County, MNborders it13562.2%5.1 pCi/L+29.5 points
Waseca County, MNborders it6360.3%5.0 pCi/L+27.6 points
Nicollet County, MNborders it12945.7%3.7 pCi/L+13.0 points
Martin County, MNborders it8143.2%3.5 pCi/L+10.5 points
Where Blue Earth County's reported results fell, 2023, beside Minnesota and the United States
ResultBlue Earth County testsBlue Earth County shareMinnesota shareU.S. shareAgainst Minnesota
Under 2 pCi/L18146.2%36.6%41.4%+9.6 points
2 to 4 pCi/L8321.2%28.9%25.2%−7.7 points
4 pCi/L and above12832.7%34.6%33.4%−1.9 points
Blue Earth County ranked among the 62 Minnesota counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Aitkin County43 of 623138.7%3.1 pCi/L
Morrison County44 of 626235.5%3.0 pCi/L
Chisago County45 of 6216634.9%2.9 pCi/L
Dakota County46 of 622,18334.6%2.9 pCi/L
Carver County47 of 6248934.6%2.8 pCi/L
Blue Earth County48 of 6239232.7%2.2 pCi/L
Hennepin County49 of 626,54532.0%2.7 pCi/L
Crow Wing County50 of 6217730.5%2.7 pCi/L
Itasca County51 of 6213726.3%1.9 pCi/L
Cass County52 of 6210625.5%2.3 pCi/L
Todd County53 of 626323.8%2.0 pCi/L
Blue Earth County radon tests by year, against Minnesota's pooled share
YearTestsAt or above 4 pCi/LMedianHighestMinnesota, pooledChange from the row before
202339232.7%2.2 pCi/L94.4 pCi/L34.6%+0.4 points
202249332.3%2.8 pCi/L54.4 pCi/L31.6%−2.1 points
202153234.4%2.2 pCi/L27.3 pCi/L33.1%−8.4 points
202025742.8%2.3 pCi/L30.1 pCi/L31.8%−10.8 points
201920753.6%4.3 pCi/L45.0 pCi/L36.1%+1.3 points
201828752.3%4.4 pCi/L38.8 pCi/L38.3%−6.3 points
201729758.6%4.7 pCi/L31.3 pCi/L38.2%−0.3 points
201641858.9%4.9 pCi/L72.7 pCi/L37.0%−3.6 points
201537662.5%5.1 pCi/L43.0 pCi/L43.6%−2.5 points
201443265.0%5.4 pCi/L51.0 pCi/L42.9%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Blue Earth County, State data

Minnesota's own radon test data

Measured

What Minnesota's own agencies publish about radon tests in Blue Earth County, with their period. These are not CDC's figures and are never added to them.

MeasuredState figures, not CDC's

What the Minnesota Department of Health reports for Blue Earth County

Radon Testing (MN Public Health Data Access Portal): home radon tests reported voluntarily by private laboratories and licensed radon measurement professionals, counted by property. Period: 2016-2025.

Share with one or more tests at or above 4 pCi/L

57.2%

1,477 properties tested with one or more tests at or above 4 pCi/L

Median result

4.3 pCi/L

Average result

5.7 pCi/L

Tests behind these figures

258 properties tested a year on average

  • MDH says these data do not include all of the radon tests conducted in Minnesota.
  • Post-mitigation tests are excluded from the averages and the median; the percentages use each property's highest test.
  • Each home is unique and can have very different results than a neighbor's home; the only way to know is to test.
  • These figures describe tests reported to the Minnesota Department of Health in this area. They count a different set of tests than CDC's figures and are not a reading of any one home.

Measured: Minnesota Department of Health data, 2016-2025.

Blue Earth County, Geology

The ground under Blue Earth County

Predicted

USGS's geologic map puts all of Blue Earth County's mapped land in one class: high radon potential. The map puts 62.7% of Blue Earth County in the area it calls Glacial Lake Deposits and 37.3% in Central Lowland-Till Prairie. USGS gives both a radon index of 14, in the high band (12 to 17).

USGS's geologic areas under Blue Earth County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Glacial Lake DepositsSilt and clay glacial lake deposits.High1462.7%
Central Lowland-Till PrairieSilty and clayey till derived from shale and sandstone.High1437.3%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Blue Earth County beside the ground around it

Blue Earth County has more high-potential ground than Minnesota as a whole: 100% of its land against 61.1%. Of the 7 counties that border it, none has as large a share of high-potential ground; Brown County comes nearest at 100%.

Share of land by USGS radon potential: Blue Earth County, the 7 counties bordering it and Minnesota
AreaEPA zoneLow potentialModerate potentialHigh potential
Blue Earth CountyZone 1NoneNone100%
Faribault CountyZone 1NoneNone100%
Nicollet CountyZone 1NoneNone100%
Waseca CountyZone 1NoneNone100%
Watonwan CountyZone 1NoneNone100%
Martin CountyZone 1NoneNone100%
Le Sueur CountyZone 1NoneNone100%
Brown CountyZone 1NoneNone100%
Minnesota87 counties, pooled by land areaVariesNone38.9%61.1%

The map rates the ground, not the air in any home.

Local help

Blue Earth County, Local resources

Radon testing and mitigation in Blue Earth County

Listed radon businesses with an address in Blue Earth County:

Listed radon professionals by town: Mankato

What Minnesota's program says
Phone
651-201-4601
Email
health.indoorair@state.mn.us
Licensing of radon professionals
The Radon Licensing Act requires anyone who performs a radon test or radon mitigation, in a building they do not own or lease, must be licensed by MDH.
Disclosure when a home is sold or rented
The Minnesota Radon Awareness Act requires specific disclosure and education be provided to potential home buyers during residential real estate transactions in Minnesota.

What it means

Blue Earth County, Questions

Questions about radon in Blue Earth County

Are radon levels high in Blue Earth County?

In 2023, 32.7% of the radon tests reported to CDC for Blue Earth County, Minnesota were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.2 pCi/L. Of 62 Minnesota counties with 30 or more tests for the same period, 47 reported a higher share; pooled, the state comes to 34.6%.

Which counties border Blue Earth County?

Blue Earth County borders 7 counties: Faribault County, Nicollet County, Waseca County, Watonwan County, Martin County, Le Sueur County and Brown County.

Products

Blue Earth County, Products

Testing a home in Blue Earth County

In Blue Earth County, 32.7% of 392 tests reported to CDC in 2023 reached 4 pCi/L, against 34.6% pooled across Minnesota. In Zone 1 the year-round level in Blue Earth County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Blue Earth County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Blue Earth County

Explore

Blue Earth County, Bordering counties

Counties bordering Blue Earth County

Calculated by Radon411

Blue Earth County, Cities and towns

Cities and towns in Blue Earth County

The Census Bureau estimates 70,634 residents in Blue Earth County for July 1, 2025, 1,432 more than in 2020 (+2.1%). That works out to 94 people per square mile of land. Mankato, the largest place on its list (46,529 residents in all), extends beyond Blue Earth County, so no share of the total is worked out for it. CDC's 392 reported tests for 2023 work out to 5.5 per 1,000 residents (2025 estimate), close to Minnesota's 3.9.

From Mankato to Pemberton, CDC publishes no figure by town: each reads Blue Earth County's.

The 12 largest cities and towns in Blue Earth County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Mankatoextends beyond Blue Earth County46,529+4.2%Counted whole
North Mankatoextends beyond Blue Earth County14,165−0.9%Counted whole
Eagle Lake3,357+2.0%4.8%
Lake Crystal2,470−2.8%3.5%
Mapleton1,622−4.9%2.3%
Madison Lake1,315+5.0%1.9%
St. Clair707−4.6%1.0%
Minnesota Lakeextends beyond Blue Earth County662+0.2%Counted whole
Good Thunder536−3.9%0.8%
Amboy507−5.6%0.7%
Vernon Center315−4.3%0.4%
Skyline283−2.7%0.4%
  • Pemberton

13 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Blue Earth County is counted whole, so it has no share.

Blue Earth County, Homes

Homes in Blue Earth County

Of Blue Earth County's 29,544 homes, 59% are detached houses, against 66% across Minnesota; 23% are in buildings of five or more homes. Half of its homes were built before 1977, close to Minnesota's 1978: 33% date from before 1960 and 28% from 2000 or later. 62% of occupied homes are lived in by their owner (Minnesota: 72%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Blue Earth County, Minnesota, 2019 to 2023
HomesBlue Earth CountyMinnesota
Housing units29,5442,519,538
Detached houses59%66%
In buildings of 5 or more23%19%
Mobile homes4%3%
Built before 196033%29%
Built since 200028%22%
Middle year built19771978
Owner-occupied62%72%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.