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 Martin County, Minnesota
EPA puts Martin County in Zone 1, its highest radon zone, and high results are common there: 43.2% of the 81 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
43.2%
8.6 pts above MN
- Martin
- 43.2%
- Minnesota
- 34.6%
81 tests, 2023
Median result
3.5pCi/L
Below action level
- Martin
- 3.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
81
37th of 62 by tests
- Martin
- 81
- 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
32 of 62
Middle half
- Martin
- 43.2%
- Renville
- 75.7%
By share, of 62 with 30+ tests
Read a result for Martin County
Starts at Martin County's median, 3.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.5 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. Martin County's median reported result, 2023.
The data
Martin County, At a glance
Martin County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Martin 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 Martin County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 74.3% |
| 2015 | 57.9% |
| 2016 | 64.2% |
| 2017 | 50.6% |
| 2018 | 55.6% |
| 2019 | 65.8% |
| 2020 | 58.6% |
| 2021 | 65.4% |
| 2022 | 76.5% |
| 2023 | 43.2% |
2023: 43.2%. Across these years the share ran from 43.2% to 76.5%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 81 tests reported to CDC for Martin 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).
Martin County, Compared
Martin County radon figures, compared
Calculated by Radon411In Martin County, about 4 in 10 reported tests in 2023 (35 of 81) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 9.8 points higher. Across 86 Minnesota counties pooled together, 34.6% of tests reached that level, so Martin County runs 8.6 points above its state.
Of 3 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 32.7% (Blue Earth County) to 70.0% (Faribault County). By share, Martin County is 32nd of 62 Minnesota counties with 30 or more tests for the same period.
Year by year, 2014 opened at 74.3% and 2023 closed at 43.2% (down 31.1 points), with 2022 the high at 76.5%. Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 94.5 pCi/L. Below the action level, 18 tests (22.2%) came in under 2 pCi/L, against 36.6% statewide, and 28 tests (34.6%) fell between 2 and 4, against 28.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 43.2% share point the same way here. USGS geology rates 100% of the county's land high radon potential.
The busiest year on file was 2015, with 114 tests reported; the quietest, 2019, had 38.
Martin CountyMinnesota, pooled
43.2% % of tests34.6% % of tests
| Year | Tests | Martin County, at or above 4 pCi/L | Minnesota, pooled |
|---|---|---|---|
| 2014 | 74 | 74.3% | 42.9% |
| 2015 | 114 | 57.9% | 43.6% |
| 2016 | 53 | 64.2% | 37.0% |
| 2017 | 81 | 50.6% | 38.2% |
| 2018 | 63 | 55.6% | 38.3% |
| 2019 | 38 | 65.8% | 36.1% |
| 2020 | 70 | 58.6% | 31.8% |
| 2021 | 52 | 65.4% | 33.1% |
| 2022 | 51 | 76.5% | 31.6% |
| 2023 | 81 | 43.2% | 34.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Martin County, State data
Minnesota's own radon test data
MeasuredWhat Minnesota's own agencies publish about radon tests in Martin 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 Martin 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
63.9%
294 properties tested with one or more tests at or above 4 pCi/L
Median result
4.5 pCi/L
Average result
6.1 pCi/L
Tests behind these figures
46 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.
Martin County, Geology
The ground under Martin County
PredictedUSGS's geologic map puts all of Martin County's mapped land in one class: high radon potential. 99.0% 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 | 99.0% |
| Des Moines Lobe | Calcareous loamy till derived from shale, limestone, dolomite, sandstone. | High | 12 | 0.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Martin County beside the ground around it
Martin 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; Blue Earth County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Martin County, Local resources
Radon testing and mitigation in Martin County
Listed radon businesses with an address in Martin 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: Welcome
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
Martin County, Questions
Questions about radon in Martin County
Are radon levels high in Martin County?
In 2023, 43.2% of the radon tests reported to CDC for Martin County, Minnesota were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 62 Minnesota counties with 30 or more tests for the same period, 31 reported a higher share; pooled, the state comes to 34.6%.
Which counties border Martin County?
Martin County borders 6 counties: Watonwan County, MN, Emmet County, IA, Faribault County, MN, Jackson County, MN, Blue Earth County, MN and Kossuth County, IA.
Products
Martin County, Products
Testing a home in Martin County
In Martin County, 43.2% of 81 tests reported to CDC in 2023 reached 4 pCi/L, against 34.6% pooled across Minnesota. In Zone 1 the year-round level in Martin 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
MonitorINKBIRD
INK-RD3 battery radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
First reading: Within 24 hours
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Martin County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Martin County
Explore
Martin County, Bordering counties
Counties bordering Martin County
Calculated by Radon411- Radon levels in Faribault County, MNEPA zone 1
70.0%at or above 4 pCi/L
Median 8.1 pCi/L · 30 tests · 26.8 points above Martin County
- Radon levels in Watonwan County, MNEPA zone 1
66.7%at or above 4 pCi/L
Median 6.2 pCi/L · 24 tests · 23.5 points above Martin County
- Radon levels in Jackson County, MNEPA zone 1
52.3%at or above 4 pCi/L
Median 4.1 pCi/L · 44 tests · 9.1 points above Martin County
- Radon levels in Blue Earth County, MNEPA zone 1
32.7%at or above 4 pCi/L
Median 2.2 pCi/L · 392 tests · 10.5 points below Martin County
- Radon levels in Emmet County, IAEPA zone 1
No CDC figure for 2023; its page reads it against its own neighbours.
- Radon levels in Kossuth County, IAEPA zone 1
No CDC figure for 2023; its page reads it against its own neighbours.
Martin County, Cities and towns
Cities and towns in Martin County
About 19,440 people live in Martin County by the Census Bureau's estimate for July 1, 2025, 558 fewer than in 2020 (−2.8%). That works out to 27 people per square mile of land. Fairmont alone is home to 10,099 of them, 51.9% of the total. CDC's 81 reported tests for 2023 work out to 4.2 per 1,000 residents (2025 estimate), close to Minnesota's 3.9.
From Fairmont to Ormsby, CDC publishes no figure by town: each reads Martin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Fairmont | 10,099 | −3.3% | 51.9% |
| Truman | 1,059 | −3.6% | 5.4% |
| Sherburn | 1,040 | −1.7% | 5.3% |
| Welcome | 687 | −3.1% | 3.5% |
| Trimont | 682 | −3.8% | 3.5% |
| Ceylon | 293 | −3.9% | 1.5% |
| Granada | 278 | −3.8% | 1.4% |
| Northrop | 216 | −4.0% | 1.1% |
| Dunnell | 131 | −0.8% | 0.7% |
| Ormsbyextends beyond Martin County | 122 | +2.5% | Counted whole |
10 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 Martin County is counted whole, so it has no share.
Martin County, Homes
Homes in Martin County
Martin County is a place of houses on their own lots: 79% of its 9,715 homes are detached single-family houses, against 66% across Minnesota. The homes are older than Minnesota's as a whole: half were built before 1958 (1978 for Minnesota), and 53% date from before 1960. 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 | Martin County | Minnesota |
|---|---|---|
| Housing units | 9,715 | 2,519,538 |
| Detached houses | 79% | 66% |
| In buildings of 5 or more | 12% | 19% |
| Mobile homes | 3% | 3% |
| Built before 1960 | 53% | 29% |
| Built since 2000 | 8% | 22% |
| Middle year built | 1958 | 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.