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 McHenry County, North Dakota
EPA puts McHenry County in Zone 1, its highest radon zone, and only 28 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
60.6%
4.3 pts above ND
- McHenry
- 60.6%
- ND
- 56.3%
33 tests, 2006 to 2015
Median result
5.5pCi/L
Action level reached
- McHenry
- 5.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2006 to 2015
Tests reported
33
34th of 36 by tests
- McHenry
- 33
- Burleigh
- 1,380
Reported to CDC before any fix, 2006 to 2015
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in ND
21 of 36
Middle half
- McHenry
- 60.6%
- Dunn
- 80.0%
By share, of 36 with 30+ tests
Read a result for McHenry County
Starts at McHenry County's median, 5.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 5.5 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. McHenry County's median reported result, 2006 to 2015.
The data
McHenry County, At a glance
McHenry County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of McHenry 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 McHenry County, 2008 to 2017, laboratory
CDC holds 28 reported tests for McHenry County over the 2008 to 2017 laboratory totals, with a median of 5.3 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). McHenry County beside the counties around it is how this page reads it.
What these figures count
Only 28 tests were reported to CDC for McHenry County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
McHenry County, Compared
McHenry County radon figures, compared
Calculated by Radon411More than half: 60.6% of the 33 radon tests reported to CDC for McHenry County over the 2006 to 2015 laboratory totals read at least 4 pCi/L. That places it 21st of 36 North Dakota counties with 30 or more tests for the same period. That is 4.3 points above the 56.3% pooled from 53 North Dakota counties.
The newest figure, over the 2008 to 2017 laboratory totals, counts only 28 tests (64.3% at or above 4 pCi/L), too few to compare, so this reading uses the 33-test figure.
The median result, 5.5 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 51.3 pCi/L. The rest split 12.1% under 2 pCi/L and 27.3% from 2 to 4 (North Dakota: 20.7% and 22.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 60.6% share point the same way here.
1 of its 4 bordering counties with figures ran higher, led by Bottineau County at 66.7%; Ward County reported 37.7%. Statewide for the same period, Dunn County reported the highest share (80.0%) and Richland County the lowest (35.1%).
CDC's ten-year totals for McHenry County went from 29 tests (2005 to 2014) to 28 (2008 to 2017), the share going from 55.2% to 64.3%.
Nationally, every county with a figure for the same period pools to 36.3%; McHenry County sits 24.3 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
McHenry County, Geology
The ground under McHenry County
PredictedUSGS's geologic map puts all of McHenry County's mapped land in one class: high radon potential. The map puts 53.3% of McHenry County in the area it calls Glacial Lakes and 46.7% in Great Plains (Glaciated). USGS gives the first a radon index of 14 and the second 13, both in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Glacial Lakes | Silt and clay deposits derived from Cretaceous shales containing higher than average amounts of uranium. | High | 14 | 53.3% |
| Great Plains (Glaciated) | Glacial deposits derived from Cretaceous shales containing higher than average amounts of uranium. | High | 13 | 46.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
McHenry County beside the ground around it
On high-potential ground McHenry County is close to North Dakota as a whole: 100% of its land against 98.9%. Of the 6 counties that border it, none has as large a share of high-potential ground; McLean County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
McHenry County, Local resources
Radon testing and mitigation in McHenry County
- North Dakota's radon programNorth Dakota Department of Environmental QualityNorth Dakota's radon program offers free or discounted test kits, and answers questions about testing and mitigation in North Dakota.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Notice: The DEQ is out of free radon test kits.
- Compare kits
- Professionals in North Dakota47 professionals are listed in North Dakota.
What North Dakota's program says
- Phone
- 701-328-5166
- jOtto@nd.gov
What it means
McHenry County, Questions
Questions about radon in McHenry County
Are radon levels high in McHenry County?
Over the 2008 to 2017 laboratory totals, 64.3% of the radon tests reported to CDC for McHenry County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.3 pCi/L. Of 36 North Dakota counties with 30 or more tests for the same period, 20 reported a higher share; pooled, the state comes to 56.3%.
Which counties border McHenry County?
McHenry County borders 6 counties: Pierce County, Ward County, Bottineau County, Sheridan County, McLean County and Renville County.
Products
McHenry County, Products
Testing a home in McHenry County
In McHenry County, 60.6% of 33 tests reported to CDC over the 2006 to 2015 laboratory totals reached 4 pCi/L, against 56.3% pooled across North Dakota. In Zone 1 the year-round level in McHenry 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
MonitorAranet
Radon One battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 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
McHenry County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like McHenry County
Explore
McHenry County, Bordering counties
Counties bordering McHenry County
Calculated by Radon411- Radon levels in Bottineau CountyEPA zone 1
66.7%at or above 4 pCi/L
Median 6.5 pCi/L · 120 tests · 6.1 points above McHenry County
- Radon levels in Sheridan CountyEPA zone 1
53.8%at or above 4 pCi/L
Median 4.2 pCi/L · 13 tests · 6.8 points below McHenry County
- Radon levels in McLean CountyEPA zone 1
52.4%at or above 4 pCi/L
Median 4.3 pCi/L · 103 tests · 8.2 points below McHenry County
- Radon levels in Renville CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 3.8 pCi/L · 8 tests · 10.6 points below McHenry County
- Radon levels in Pierce CountyEPA zone 1
45.0%at or above 4 pCi/L
Median 3.8 pCi/L · 40 tests · 15.6 points below McHenry County
- Radon levels in Ward CountyEPA zone 1
37.7%at or above 4 pCi/L
Median 3.0 pCi/L · 623 tests · 22.9 points below McHenry County
McHenry County, Cities and towns
Cities and towns in McHenry County
About 5,130 people live in McHenry County by the Census Bureau's estimate for July 1, 2025, 206 fewer than in 2020 (−3.9%). Spread over its land, that is 2.7 people to the square mile. Its largest town, Velva, has 1,046 residents, 20.4% of the total. CDC's 33 reported tests for 2006 to 2015 work out to 6.4 per 1,000 residents (2025 estimate), close to North Dakota's 8.4.
From Velva to Bantry, CDC publishes no figure by town: each reads McHenry County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Velva | 1,046 | −4.6% | 20.4% |
| Towner | 454 | −4.8% | 8.8% |
| Drake | 277 | −5.1% | 5.4% |
| Granville | 231 | −2.5% | 4.5% |
| Anamoose | 216 | −3.1% | 4.2% |
| Upham | 130 | −3.0% | 2.5% |
| Deering | 93 | Level | 1.8% |
| Karlsruhe | 86 | −2.3% | 1.7% |
| Voltaire | 43 | −4.4% | 0.8% |
| Balfour | 16 | −5.9% | 0.3% |
| Bergen | 12 | −7.7% | 0.2% |
| Kief | 7 | Level | 0.1% |
- Bantry
13 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).
McHenry County, Homes
Homes in McHenry County
McHenry County is a place of houses on their own lots: 81% of its 2,832 homes are detached single-family houses, against 57% across North Dakota. The homes are older than North Dakota's as a whole: half were built before 1965 (1981 for North Dakota), and 42% date from before 1960. Owners live in 80% of the occupied homes (North Dakota: 63%), so for most households a test and a fix are their own to order.
| Homes | McHenry County | North Dakota |
|---|---|---|
| Housing units | 2,832 | 374,866 |
| Detached houses | 81% | 57% |
| In buildings of 5 or more | 5% | 25% |
| Mobile homes | 10% | 7% |
| Built before 1960 | 42% | 24% |
| Built since 2000 | 12% | 31% |
| Middle year built | 1965 | 1981 |
| Owner-occupied | 80% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.