Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Big Stone County, Minnesota
EPA puts Big Stone County in Zone 1, its highest radon zone, and only 18 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
61.6%
17.4 pts above MN
- Big Stone
- 61.6%
- Minnesota
- 44.2%
219 tests, 2005 to 2014
Median result
4.9pCi/L
Action level reached
- Big Stone
- 4.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2005 to 2014
Tests reported
219
69th of 87 by tests
- Big Stone
- 219
- Hennepin
- 32,450
Reported to CDC before any fix, 2005 to 2014
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
35 of 87
Middle half
- Big Stone
- 61.6%
- Rock
- 85.0%
By share, of 87 with 30+ tests
Read a result for Big Stone County
Starts at Big Stone County's median, 4.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.9 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Big Stone County's median reported result, 2005 to 2014.
The data
Big Stone County, At a glance
Big Stone County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Big Stone 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 Big Stone County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 46.7% |
| 2015 | 55.6% |
| 2016 | 68.3% |
| 2017 | 61.9% |
| 2018 | 40.9% |
| 2019 | 50.0% |
| 2020 | 31.6% |
| 2021 | 56.3% |
| 2022 | 52.9% |
| 2023 | 61.1% |
2023: 61.1%. Across these years the share ran from 31.6% to 68.3%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 18 tests were reported to CDC for Big Stone County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Big Stone County, Compared
Big Stone County radon figures, compared
Calculated by Radon411More than half: 61.6% of the 219 radon tests reported to CDC for Big Stone County over the 2005 to 2014 laboratory totals read at least 4 pCi/L. That places it 35th of 87 Minnesota counties with 30 or more tests for the same period. That is 17.4 points above the 44.2% pooled from 87 Minnesota counties.
The newest figure, in 2023, counts only 18 tests (61.1% at or above 4 pCi/L), too few to compare, so this reading uses the 219-test figure.
The median result, 4.9 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 56.9 pCi/L. The rest split 13.2% under 2 pCi/L and 25.1% from 2 to 4 (Minnesota: 26.4% and 29.3%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 61.6% share point the same way here.
3 of its 5 bordering counties with figures ran higher, led by Traverse County at 69.4%; Swift County reported 50.0%. Statewide for the same period, Rock County reported the highest share (85.0%) and Anoka County the lowest (16.4%).
The busiest year on file was 2016, with 41 tests reported; the quietest, 2021, had 16.
Over 3 years of annual figures the share rose 21.6 points, from 46.7% in 2014 to 68.3% in 2016; its peak was 68.3% in 2016. Nationally, every county with a figure for the same period pools to 36.0%; Big Stone County sits 25.6 points above it. CDC also counts 28 tests taken after mitigation in Big Stone County for the same period: tests in homes where a fix was already in.
Big Stone CountyMinnesota, pooled
68.3% % of tests37.0% % of tests
| Year | Tests | Big Stone County, at or above 4 pCi/L | Minnesota, pooled |
|---|---|---|---|
| 2014 | 30 | 46.7% | 42.9% |
| 2015 | 36 | 55.6% | 43.6% |
| 2016 | 41 | 68.3% | 37.0% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Big Stone County, State data
Minnesota's own radon test data
MeasuredWhat Minnesota's own agencies publish about radon tests in Big Stone 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 Big Stone 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
59.5%
88 properties tested with one or more tests at or above 4 pCi/L
Median result
4.2 pCi/L
Average result
6.0 pCi/L
Tests behind these figures
15 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.
Big Stone County, Geology
The ground under Big Stone County
PredictedUSGS's geologic map puts all of Big Stone County's mapped land in one class: high radon potential. The map puts 87.3% of Big Stone County in the area it calls Central Lowland-Till Prairie and 12.4% in Glacial Lake Deposits. USGS gives both 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 | 87.3% |
| Glacial Lake Deposits | Silt and clay glacial lake deposits. | High | 14 | 12.4% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Big Stone County beside the ground around it
Big Stone County has more high-potential ground than Minnesota as a whole: 100% of its land against 61.1%. Of the 6 counties that border it, none has as large a share of high-potential ground; Grant County, SD comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Big Stone County, Local resources
Radon testing and mitigation in Big Stone 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.
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
Big Stone County, Questions
Questions about radon in Big Stone County
Are radon levels high in Big Stone County?
In 2023, 61.1% of the radon tests reported to CDC for Big Stone County, Minnesota were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.0 pCi/L. Of 87 Minnesota counties with 30 or more tests for the same period, 34 reported a higher share; pooled, the state comes to 44.2%.
Which counties border Big Stone County?
Big Stone County borders 6 counties: Stevens County, MN, Lac qui Parle County, MN, Grant County, SD, Traverse County, MN, Swift County, MN and Roberts County, SD.
Products
Big Stone County, Products
Testing a home in Big Stone County
In Big Stone County, 61.6% of 219 tests reported to CDC over the 2005 to 2014 laboratory totals reached 4 pCi/L, against 44.2% pooled across Minnesota. In Zone 1 the year-round level in Big Stone 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
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Big Stone County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Big Stone County
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Big Stone County, Bordering counties
Counties bordering Big Stone County
Calculated by Radon411- Radon levels in Traverse County, MNEPA zone 1
69.4%at or above 4 pCi/L
Median 5.4 pCi/L · 85 tests · 7.8 points above Big Stone County
- Radon levels in Lac qui Parle County, MNEPA zone 1
67.2%at or above 4 pCi/L
Median 5.6 pCi/L · 357 tests · 5.6 points above Big Stone County
- Radon levels in Stevens County, MNEPA zone 1
63.5%at or above 4 pCi/L
Median 5.3 pCi/L · 252 tests · 1.9 points above Big Stone County
- Radon levels in Grant County, SDEPA zone 1
61.4%at or above 4 pCi/L
Median 5.8 pCi/L · 83 tests · 0.2 points below Big Stone County
- Radon levels in Swift County, MNEPA zone 1
50.0%at or above 4 pCi/L
Median 4.0 pCi/L · 414 tests · 11.6 points below Big Stone County
- Radon levels in Roberts County, SDEPA zone 1
45.0%at or above 4 pCi/L
Median 3.5 pCi/L · 20 tests · 16.6 points below Big Stone County
Big Stone County, Cities and towns
Cities and towns in Big Stone County
About 5,054 people live in Big Stone County by the Census Bureau's estimate for July 1, 2025, 104 fewer than in 2020 (−2.0%). That works out to 10 people per square mile of land. Its largest town, Ortonville, has 1,967 residents, 38.9% of the total. Together its 8 incorporated places hold 63.7% of those residents; the other 36.3% live outside any of them. Testing is reported here more often than across the state: CDC's 219 reported tests for 2005 to 2014 come to 43.3 for every 1,000 residents (2025 estimate), against 19.9 for Minnesota.
From Ortonville to Barry, CDC publishes no figure by town: each reads Big Stone County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ortonville | 1,967 | −2.8% | 38.9% |
| Graceville | 508 | −2.5% | 10.1% |
| Clinton | 369 | −3.7% | 7.3% |
| Beardsley | 207 | −3.3% | 4.1% |
| Odessa | 102 | −1.9% | 2.0% |
| Correll | 27 | −3.6% | 0.5% |
| Johnson | 23 | −4.2% | 0.5% |
| Barry | 14 | Level | 0.3% |
8 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).
Big Stone County, Homes
Homes in Big Stone County
Big Stone County is a place of houses on their own lots: 83% of its 2,984 homes are detached single-family houses, against 66% across Minnesota. The homes are older than Minnesota's as a whole: half were built before 1957 (1978 for Minnesota), and 54% date from before 1960. Owners live in 79% of the occupied homes (Minnesota: 72%), so for most households a test and a fix are their own to order.
| Homes | Big Stone County | Minnesota |
|---|---|---|
| Housing units | 2,984 | 2,519,538 |
| Detached houses | 83% | 66% |
| In buildings of 5 or more | 8% | 19% |
| Mobile homes | 6% | 3% |
| Built before 1960 | 54% | 29% |
| Built since 2000 | 11% | 22% |
| Middle year built | 1957 | 1978 |
| Owner-occupied | 79% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.