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 Olmsted County, Minnesota
EPA puts Olmsted County in Zone 1, its highest radon zone, and high results are common there: 46.1% of the 854 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
46.1%
11.5 pts above MN
- Olmsted
- 46.1%
- Minnesota
- 34.6%
854 tests, 2023
Median result
3.7pCi/L
Below action level
- Olmsted
- 3.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
854
6th of 62 by tests
- Olmsted
- 854
- 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
28 of 62
Middle half
- Olmsted
- 46.1%
- Renville
- 75.7%
By share, of 62 with 30+ tests
Read a result for Olmsted County
Starts at Olmsted 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. Olmsted County's median reported result, 2023.
The data
Olmsted County, At a glance
Olmsted County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Olmsted 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 Olmsted County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 55.1% |
| 2015 | 51.2% |
| 2016 | 47.2% |
| 2017 | 51.4% |
| 2018 | 49.2% |
| 2019 | 44.3% |
| 2020 | 32.9% |
| 2021 | 42.2% |
| 2022 | 44.4% |
| 2023 | 46.1% |
2023: 46.1%. Across these years the share ran from 32.9% to 55.1%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 854 tests reported to CDC for Olmsted 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).
Olmsted County, Compared
Olmsted County radon figures, compared
Calculated by Radon411In Olmsted County, about 5 in 10 reported tests in 2023 (394 of 854) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 12.7 points higher. Across 86 Minnesota counties pooled together, 34.6% of tests reached that level, so Olmsted County runs 11.5 points above its state.
Of 6 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 38.8% (Winona County) to 63.2% (Dodge County). By share, Olmsted County is 28th of 62 Minnesota counties with 30 or more tests for the same period.
Year by year, 2014 opened at 55.1% and 2023 closed at 46.1% (down 9.0 points), with 2014 the high at 55.1%. Half the tests came in under 3.7 pCi/L and half over it; the single highest reached 38.3 pCi/L. Below the action level, 220 tests (25.8%) came in under 2 pCi/L, against 36.6% statewide, and 240 tests (28.1%) fell between 2 and 4, against 28.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 46.1% 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 1,356 tests reported; the quietest, 2019, had 632.
Olmsted CountyMinnesota, pooled
46.1% % of tests34.6% % of tests
| Year | Tests | Olmsted County, at or above 4 pCi/L | Minnesota, pooled |
|---|---|---|---|
| 2014 | 1,356 | 55.1% | 42.9% |
| 2015 | 1,111 | 51.2% | 43.6% |
| 2016 | 1,303 | 47.2% | 37.0% |
| 2017 | 1,192 | 51.4% | 38.2% |
| 2018 | 1,314 | 49.2% | 38.3% |
| 2019 | 632 | 44.3% | 36.1% |
| 2020 | 779 | 32.9% | 31.8% |
| 2021 | 1,117 | 42.2% | 33.1% |
| 2022 | 835 | 44.4% | 31.6% |
| 2023 | 854 | 46.1% | 34.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Olmsted County, State data
Minnesota's own radon test data
MeasuredWhat Minnesota's own agencies publish about radon tests in Olmsted 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 Olmsted 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
41.7%
4,805 properties tested with one or more tests at or above 4 pCi/L
Median result
3.2 pCi/L
Average result
4.4 pCi/L
Tests behind these figures
1,153 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.
Olmsted County, Geology
The ground under Olmsted County
PredictedUSGS's geologic map puts all of Olmsted County's mapped land in one class: high radon potential. The map puts 61.8% of Olmsted County in the area it calls Driftless Section and 38.2% in Dissected Till Plains. USGS gives both a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Driftless Section | Ordivician carbonates and sandstones. | High | 12 | 61.8% |
| Dissected Till Plains | Pre-Wisconsinan glacial deposits derived from limestone, dolomite, sandstone, shale, locally covered by Wisconsinan loess. | High | 12 | 38.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Olmsted County beside the ground around it
Olmsted 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; Dodge County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Olmsted County, Local resources
Radon testing and mitigation in Olmsted County
Listed radon businesses with an address in Olmsted 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: Rochester, Eyota
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
Olmsted County, Questions
Questions about radon in Olmsted County
Are radon levels high in Olmsted County?
In 2023, 46.1% of the radon tests reported to CDC for Olmsted 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, 27 reported a higher share; pooled, the state comes to 34.6%.
Which counties border Olmsted County?
Olmsted County borders 6 counties: Wabasha County, Dodge County, Fillmore County, Mower County, Winona County and Goodhue County.
Products
Olmsted County, Products
Testing a home in Olmsted County
In Olmsted County, 46.1% of 854 tests reported to CDC in 2023 reached 4 pCi/L, against 34.6% pooled across Minnesota. In Zone 1 the year-round level in Olmsted 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
Wave Radon battery smart radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Olmsted County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Olmsted County
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Olmsted County, Bordering counties
Counties bordering Olmsted County
Calculated by Radon411- Radon levels in Dodge CountyEPA zone 1
63.2%at or above 4 pCi/L
Median 4.7 pCi/L · 155 tests · 17.1 points above Olmsted County
- Radon levels in Fillmore CountyEPA zone 1
53.4%at or above 4 pCi/L
Median 4.2 pCi/L · 118 tests · 7.3 points above Olmsted County
- Radon levels in Goodhue CountyEPA zone 1
49.5%at or above 4 pCi/L
Median 3.9 pCi/L · 218 tests · 3.4 points above Olmsted County
- Radon levels in Mower CountyEPA zone 1
45.1%at or above 4 pCi/L
Median 3.7 pCi/L · 91 tests · 1.0 points below Olmsted County
- Radon levels in Wabasha CountyEPA zone 1
42.3%at or above 4 pCi/L
Median 3.3 pCi/L · 111 tests · 3.8 points below Olmsted County
- Radon levels in Winona CountyEPA zone 1
38.8%at or above 4 pCi/L
Median 3.0 pCi/L · 139 tests · 7.3 points below Olmsted County
Olmsted County, Cities and towns
Cities and towns in Olmsted County
The Census Bureau estimates 166,731 residents in Olmsted County for July 1, 2025, 3,676 more than in 2020 (+2.3%). That works out to 255 people per square mile of land. Rochester alone is home to 124,292 of them, 74.5% of the total. CDC's 854 reported tests for 2023 work out to 5.1 per 1,000 residents (2025 estimate), close to Minnesota's 3.9.
From Rochester to Dover, CDC publishes no figure by town: each reads Olmsted County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Rochester | 124,292 | +2.2% | 74.5% |
| Stewartville | 6,850 | +2.5% | 4.1% |
| Byron | 6,740 | +6.5% | 4.0% |
| Pine Islandextends beyond Olmsted County | 3,911 | +3.4% | Counted whole |
| Chatfieldextends beyond Olmsted County | 3,018 | +0.5% | Counted whole |
| Oronoco | 2,043 | +12.3% | 1.2% |
| Eyota | 2,013 | +0.8% | 1.2% |
| Dover | 761 | −3.2% | 0.5% |
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). A place that extends beyond Olmsted County is counted whole, so it has no share.
Olmsted County, Homes
Homes in Olmsted County
Of Olmsted County's 70,255 homes, 64% are detached houses, against 66% across Minnesota; 19% are in buildings of five or more homes. Much of Olmsted County is recent building: 32% of its homes have gone up since 2000 and the middle year built is 1987, against 1978 for Minnesota. 71% 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 | Olmsted County | Minnesota |
|---|---|---|
| Housing units | 70,255 | 2,519,538 |
| Detached houses | 64% | 66% |
| In buildings of 5 or more | 19% | 19% |
| Mobile homes | 3% | 3% |
| Built before 1960 | 19% | 29% |
| Built since 2000 | 32% | 22% |
| Middle year built | 1987 | 1978 |
| Owner-occupied | 71% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.