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 Polk County, Minnesota
EPA puts Polk County in Zone 1, its highest radon zone, and high results are common there: 60.0% of the 90 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
60.0%
25.4 pts above MN
- Polk
- 60.0%
- Minnesota
- 34.6%
90 tests, 2023
Median result
4.7pCi/L
Action level reached
- Polk
- 4.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
90
36th of 62 by tests
- Polk
- 90
- 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
13 of 62
Top quarter
- Polk
- 60.0%
- Renville
- 75.7%
By share, of 62 with 30+ tests
Read a result for Polk County
Starts at Polk County's median, 4.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.7 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. Polk County's median reported result, 2023.
The data
Polk County, At a glance
Polk County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Polk County in
USGS geologic potential: High across 97% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Polk County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 71.2% |
| 2015 | 60.6% |
| 2016 | 69.6% |
| 2017 | 69.4% |
| 2018 | 85.4% |
| 2019 | 21.6% |
| 2020 | 50.0% |
| 2021 | 67.6% |
| 2022 | 59.4% |
| 2023 | 60.0% |
2023: 60.0%. Across these years the share ran from 21.6% to 85.4%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 90 tests reported to CDC for Polk 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).
Polk County, Compared
Polk County radon figures, compared
Calculated by Radon411More than half: 60.0% of the 90 radon tests reported to CDC for Polk County in 2023 read at least 4 pCi/L. That places it 13th of 62 Minnesota counties with 30 or more tests for the same period. That is 25.4 points above the 34.6% pooled from 86 Minnesota counties.
The median result, 4.7 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 32.7 pCi/L. The rest split 18.9% under 2 pCi/L and 21.1% from 2 to 4 (Minnesota: 36.6% and 28.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 60.0% share point the same way here.
Statewide for the same period, Renville County reported the highest share (75.7%) and Lake County the lowest (3.8%).
The busiest year on file was 2014, with 205 tests reported; the quietest, 2020, had 50.
Over 10 years of annual figures the share fell 11.2 points, from 71.2% in 2014 to 60.0% in 2023; its peak was 85.4% in 2018. Nationally, every county with a figure for the same period pools to 33.4%; Polk County sits 26.6 points above it.
Polk CountyMinnesota, pooled
60.0% % of tests34.6% % of tests
| Year | Tests | Polk County, at or above 4 pCi/L | Minnesota, pooled |
|---|---|---|---|
| 2014 | 205 | 71.2% | 42.9% |
| 2015 | 109 | 60.6% | 43.6% |
| 2016 | 92 | 69.6% | 37.0% |
| 2017 | 108 | 69.4% | 38.2% |
| 2018 | 96 | 85.4% | 38.3% |
| 2019 | 139 | 21.6% | 36.1% |
| 2020 | 50 | 50.0% | 31.8% |
| 2021 | 74 | 67.6% | 33.1% |
| 2022 | 64 | 59.4% | 31.6% |
| 2023 | 90 | 60.0% | 34.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Polk County, State data
Minnesota's own radon test data
MeasuredWhat Minnesota's own agencies publish about radon tests in Polk 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 Polk 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
69.9%
387 properties tested with one or more tests at or above 4 pCi/L
Median result
6.8 pCi/L
Average result
9.1 pCi/L
Tests behind these figures
55 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.
Polk County, Geology
The ground under Polk County
PredictedMost of the ground under Polk County is one class on USGS's geologic map: 96.5% of its land is high radon potential, with 3.5% moderate. The map puts 72.8% of Polk County in the area it calls Lake Agassiz Plain and 23.7% in Central Lowland-Till Prairie, with one smaller area beside them. USGS gives the first a radon index of 15 and the second 14, both in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Lake Agassiz Plain | Silt and clay deposits of Glacial Lake Agassiz derived from Cretaceous shales containing higher than average amounts of uranium. | High | 15 | 72.8% |
| Central Lowland-Till Prairie | Silty and clayey till derived from shale and sandstone. | High | 14 | 23.7% |
| Lake Agassiz Plain/Central Lowland-Western Lake Section | Silty and clayey glacial deposits and lake deposits. | Moderate | 10 | 3.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Polk County beside the ground around it
Polk County has more high-potential ground than Minnesota as a whole: 96.5% of its land against 61.1%. Of the 8 counties that border it, 4 have more high-potential ground, Grand Forks County, ND the most at 100%.
The map rates the ground, not the air in any home.
Local help
Polk County, Local resources
Radon testing and mitigation in Polk 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
Polk County, Questions
Questions about radon in Polk County
Are radon levels high in Polk County?
In 2023, 60.0% of the radon tests reported to CDC for Polk County, Minnesota were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.7 pCi/L. Of 62 Minnesota counties with 30 or more tests for the same period, 12 reported a higher share; pooled, the state comes to 34.6%.
Which counties border Polk County?
Polk County borders 8 counties: Red Lake County, MN, Traill County, ND, Pennington County, MN, Norman County, MN, Marshall County, MN, Grand Forks County, ND, Mahnomen County, MN and Clearwater County, MN.
Products
Polk County, Products
Testing a home in Polk County
In Polk County, 60.0% of 90 tests reported to CDC in 2023 reached 4 pCi/L, against 34.6% pooled across Minnesota. In Zone 1 the year-round level in Polk 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
RM-65 rechargeable radon detector with a color screen and alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
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
Polk County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Polk County
Explore
Polk County, Bordering counties
Counties bordering Polk County
Calculated by Radon411- Radon levels in Mahnomen County, MNEPA zone 1
54.5%at or above 4 pCi/L
Median 5.1 pCi/L · 11 tests · 5.5 points below Polk County
- Radon levels in Clearwater County, MNEPA zone 2
54.5%at or above 4 pCi/L
Median 4.7 pCi/L · 11 tests · 5.5 points below Polk County
- Radon levels in Pennington County, MNEPA zone 1
53.3%at or above 4 pCi/L
Median 4.5 pCi/L · 15 tests · 6.7 points below Polk County
- Radon levels in Red Lake County, MNEPA zone 1
50.0%at or above 4 pCi/L
Median 3.0 pCi/L · 2 tests · 10.0 points below Polk County
- Radon levels in Norman County, MNEPA zone 1
37.5%at or above 4 pCi/L
Median 3.0 pCi/L · 8 tests · 22.5 points below Polk County
- Radon levels in Marshall County, MNEPA zone 1
9.1%at or above 4 pCi/L
Median 2.2 pCi/L · 11 tests · 50.9 points below Polk County
- Radon levels in Traill County, NDEPA zone 1
No CDC figure for 2023; its page reads it against its own neighbours.
- Radon levels in Grand Forks County, NDEPA zone 1
No CDC figure for 2023; its page reads it against its own neighbours.
Polk County, Cities and towns
Cities and towns in Polk County
About 30,545 people live in Polk County by the Census Bureau's estimate for July 1, 2025, 554 fewer than in 2020 (−1.8%). That works out to 15 people per square mile of land. Its largest town, East Grand Forks, has 8,906 residents, 29.2% of the total. Together its 15 incorporated places hold 67.7% of those residents; the other 32.3% live outside any of them. CDC's 90 reported tests for 2023 work out to 2.9 per 1,000 residents (2025 estimate), close to Minnesota's 3.9.
From East Grand Forks to Trail, CDC publishes no figure by town: each reads Polk County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| East Grand Forks | 8,906 | −2.7% | 29.2% |
| Crookston | 7,375 | −1.4% | 24.1% |
| Fosston | 1,383 | −3.6% | 4.5% |
| Fertile | 777 | −2.5% | 2.5% |
| McIntosh | 577 | −3.8% | 1.9% |
| Fisher | 402 | −4.1% | 1.3% |
| Erskine | 384 | −4.2% | 1.3% |
| Climax | 240 | −0.8% | 0.8% |
| Winger | 178 | −0.6% | 0.6% |
| Mentor | 107 | −3.6% | 0.4% |
| Lengby | 90 | −2.2% | 0.3% |
| Beltrami | 86 | −4.4% | 0.3% |
- Nielsville
- Gully
- Trail
15 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).
Polk County, Homes
Homes in Polk County
Of Polk County's 14,670 homes, 72% are detached houses, against 66% across Minnesota; 15% are in buildings of five or more homes. Half of its homes were built before 1971, close to Minnesota's 1978: 38% date from before 1960 and 16% 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 | Polk County | Minnesota |
|---|---|---|
| Housing units | 14,670 | 2,519,538 |
| Detached houses | 72% | 66% |
| In buildings of 5 or more | 15% | 19% |
| Mobile homes | 6% | 3% |
| Built before 1960 | 38% | 29% |
| Built since 2000 | 16% | 22% |
| Middle year built | 1971 | 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.