Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Nicollet County, Minnesota
EPA puts Nicollet County in Zone 1, its highest radon zone, and high results are common there: 45.7% of the 129 radon tests reported to CDC (2023) came back 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
Share at 4+ pCi/L
45.7%
11.1 pts above MN
- Nicollet
- 45.7%
- Minnesota
- 34.6%
129 tests, 2023
Median result
3.7pCi/L
Below action level
- Nicollet
- 3.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
129
26th of 62 by tests
- Nicollet
- 129
- Hennepin
- 6,545
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Minnesota
30 of 62
Middle half
- Nicollet
- 45.7%
- Renville
- 75.7%
By share, of 62 with 30+ tests
Read a result for Nicollet County
Starts at Nicollet County's median, 3.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.7 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Nicollet County's median reported result, 2023.
The data
Nicollet County, At a glance
Nicollet County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Nicollet County in
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 Nicollet County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 59.2% |
| 2015 | 61.0% |
| 2016 | 55.8% |
| 2017 | 54.8% |
| 2018 | 58.1% |
| 2019 | 64.1% |
| 2020 | 39.7% |
| 2021 | 39.6% |
| 2022 | 54.7% |
| 2023 | 45.7% |
2023: 45.7%. Across these years the share ran from 39.6% to 64.1%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 129 tests reported to CDC for Nicollet 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).
Nicollet County, Compared
Nicollet County radon figures, compared
Calculated by Radon411In Nicollet County, about 5 in 10 reported tests in 2023 (59 of 129) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 12.3 points higher. Across 86 Minnesota counties pooled together, 34.6% of tests reached that level, so Nicollet County runs 11.1 points above its state.
Of 5 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 32.7% (Blue Earth County) to 75.7% (Renville County). By share, Nicollet County is 30th of 62 Minnesota counties with 30 or more tests for the same period.
Year by year, 2014 opened at 59.2% and 2023 closed at 45.7% (down 13.5 points), with 2019 the high at 64.1%. Half the tests came in under 3.7 pCi/L and half over it; the single highest reached 29.5 pCi/L. Below the action level, 38 tests (29.5%) came in under 2 pCi/L, against 36.6% statewide, and 32 tests (24.8%) fell between 2 and 4, against 28.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 45.7% share point the same way here. USGS geology rates 100% of the county's land high radon potential.
The busiest year on file was 2014, with 402 tests reported; the quietest, 2019, had 78.
Nicollet CountyMinnesota, pooled
45.7% % of tests34.6% % of tests
| Year | Tests | Nicollet County, at or above 4 pCi/L | Minnesota, pooled |
|---|---|---|---|
| 2014 | 402 | 59.2% | 42.9% |
| 2015 | 305 | 61.0% | 43.6% |
| 2016 | 251 | 55.8% | 37.0% |
| 2017 | 270 | 54.8% | 38.2% |
| 2018 | 320 | 58.1% | 38.3% |
| 2019 | 78 | 64.1% | 36.1% |
| 2020 | 262 | 39.7% | 31.8% |
| 2021 | 212 | 39.6% | 33.1% |
| 2022 | 170 | 54.7% | 31.6% |
| 2023 | 129 | 45.7% | 34.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Nicollet County, State data
Minnesota's own radon test data
MeasuredWhat Minnesota's own agencies publish about radon tests in Nicollet 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 Nicollet 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
55.6%
959 properties tested with one or more tests at or above 4 pCi/L
Median result
4.2 pCi/L
Average result
5.4 pCi/L
Tests behind these figures
173 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.
Nicollet County, Geology
The ground under Nicollet County
PredictedUSGS's geologic map puts all of Nicollet County's mapped land in one class: high radon potential. All of it lies in the area the map calls Central Lowland-Till Prairie, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Central Lowland-Till Prairie | Silty and clayey till derived from shale and sandstone. | High | 14 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Nicollet County beside the ground around it
Nicollet County has more high-potential ground than Minnesota as a whole: 100% of its land against 61.1%. Of the 5 counties that border it, none has as large a share of high-potential ground; Blue Earth County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Nicollet County, Local resources
Radon testing and mitigation in Nicollet County
Listed radon businesses with an address in Nicollet County:
- MDH Indoor Air UnitMDH Indoor Air Unit, run by MN Dept. of Health, licenses or certifies radon professionals and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Minnesota.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Minnesota255 professionals are listed in Minnesota.
Listed radon professionals by town: Mankato, Courtland
What Minnesota's program says
- Phone
- 651-201-4601
- 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
Nicollet County, Questions
Questions about radon in Nicollet County
Are radon levels high in Nicollet County?
In 2023, 45.7% of the radon tests reported to CDC for Nicollet County, Minnesota were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.7 pCi/L. Of 62 Minnesota counties with 30 or more tests for the same period, 29 reported a higher share; pooled, the state comes to 34.6%.
Which counties border Nicollet County?
Nicollet County borders 5 counties: Sibley County, Brown County, Blue Earth County, Le Sueur County and Renville County.
Products
Nicollet County, Products
Testing a home in Nicollet County
In Nicollet County, 45.7% of 129 tests reported to CDC in 2023 reached 4 pCi/L, against 34.6% pooled across Minnesota. In Zone 1 the year-round level in Nicollet 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
Monitor
Corentium Home 2 battery digital radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Nicollet County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Nicollet County
Explore
Nicollet County, Bordering counties
Counties bordering Nicollet County
Calculated by Radon411- Radon levels in Renville CountyEPA zone 1
75.7%at or above 4 pCi/L
Median 6.3 pCi/L · 37 tests · 30.0 points above Nicollet County
- Radon levels in Brown CountyEPA zone 1
63.5%at or above 4 pCi/L
Median 5.4 pCi/L · 115 tests · 17.8 points above Nicollet County
- Radon levels in Le Sueur CountyEPA zone 1
62.2%at or above 4 pCi/L
Median 5.1 pCi/L · 135 tests · 16.5 points above Nicollet County
- Radon levels in Sibley CountyEPA zone 1
60.0%at or above 4 pCi/L
Median 5.0 pCi/L · 55 tests · 14.3 points above Nicollet County
- Radon levels in Blue Earth CountyEPA zone 1
32.7%at or above 4 pCi/L
Median 2.2 pCi/L · 392 tests · 13.0 points below Nicollet County
Nicollet County, Cities and towns
Cities and towns in Nicollet County
About 34,273 people live in Nicollet County by the Census Bureau's estimate for July 1, 2025, 231 fewer than in 2020 (−0.7%). That works out to 76 people per square mile of land. Mankato, the largest place on its list (46,529 residents in all), extends beyond Nicollet County, so no share of the total is worked out for it. CDC's 129 reported tests for 2023 work out to 3.8 per 1,000 residents (2025 estimate), close to Minnesota's 3.9.
From Mankato to Lafayette, CDC publishes no figure by town: each reads Nicollet County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Mankatoextends beyond Nicollet County | 46,529 | +4.2% | Counted whole |
| North Mankatoextends beyond Nicollet County | 14,165 | −0.9% | Counted whole |
| St. Peter | 12,275 | +1.6% | 35.8% |
| Nicollet | 1,127 | −1.6% | 3.3% |
| Courtland | 714 | −2.9% | 2.1% |
| Lafayette | 462 | −5.9% | 1.3% |
Places in Nicollet County with a city page: 1 of 1
6 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Nicollet County is counted whole, so it has no share.
Nicollet County, Homes
Homes in Nicollet County
Of Nicollet County's 13,530 homes, 68% are detached houses, against 66% across Minnesota; 15% are in buildings of five or more homes. Half of its homes were built before 1979, close to Minnesota's 1978: 27% date from before 1960 and 26% from 2000 or later. 72% 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 | Nicollet County | Minnesota |
|---|---|---|
| Housing units | 13,530 | 2,519,538 |
| Detached houses | 68% | 66% |
| In buildings of 5 or more | 15% | 19% |
| Mobile homes | 5% | 3% |
| Built before 1960 | 27% | 29% |
| Built since 2000 | 26% | 22% |
| Middle year built | 1979 | 1978 |
| Owner-occupied | 72% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.