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 Mountrail County, North Dakota
EPA puts Mountrail County in Zone 1, its highest radon zone, and high results are common there: 66.7% of the 48 radon tests reported to CDC (2008 to 2017, laboratory totals) 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
66.7%
7.4 pts above ND
- Mountrail
- 66.7%
- ND
- 59.3%
48 tests, 2008 to 2017
Median result
7.3pCi/L
Action level reached
- Mountrail
- 7.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
48
20th of 29 by tests
- Mountrail
- 48
- Burleigh
- 1,558
Reported to CDC before any fix, 2008 to 2017
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
13 of 29
Middle half
- Mountrail
- 66.7%
- Pembina
- 82.5%
By share, of 29 with 30+ tests
Read a result for Mountrail County
Starts at Mountrail County's median, 7.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 7.3 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. Mountrail County's median reported result, 2008 to 2017.
The data
Mountrail County, At a glance
Mountrail County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Mountrail 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 Mountrail County, 2008 to 2017, laboratory
Under 2 pCi/L: 14%2 to 4 pCi/L: 19%4 pCi/L and above: 67%
Of 48 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 7 | 14.6% |
| 2 to 4 pCi/L | 9 | 18.8% |
| 4 pCi/L and above | 32 | 66.7% |
What these figures count
These are the 48 tests reported to CDC for Mountrail County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Mountrail County, Compared
Mountrail County radon figures, compared
Calculated by Radon411More than half: 66.7% of the 48 radon tests reported to CDC for Mountrail County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 13th of 29 North Dakota counties with 30 or more tests for the same period. That is 7.4 points above the 59.3% pooled from 53 North Dakota counties.
The median result, 7.3 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 44.0 pCi/L. The rest split 14.6% under 2 pCi/L and 18.8% from 2 to 4 (North Dakota: 18.3% and 22.4%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 66.7% share point the same way here.
1 of its 5 bordering counties with figures ran higher, led by Dunn County at 74.3%; Williams County reported 33.8%. Statewide for the same period, Pembina County reported the highest share (82.5%) and Williams County the lowest (33.8%).
CDC's ten-year totals for Mountrail County went from 55 tests (2005 to 2014) to 48 (2008 to 2017), the share going from 63.6% to 66.7%.
Nationally, every county with a figure for the same period pools to 35.7%; Mountrail County sits 31.0 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Mountrail County, Geology
The ground under Mountrail County
PredictedUSGS's geologic map puts all of Mountrail County's mapped land in one class: high radon potential. All of it lies in the area the map calls Great Plains (Glaciated), to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Great Plains (Glaciated) | Glacial deposits derived from Cretaceous shales containing higher than average amounts of uranium. | High | 13 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Mountrail County beside the ground around it
On high-potential ground Mountrail 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; Burke County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Mountrail County, Local resources
Radon testing and mitigation in Mountrail 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
Mountrail County, Questions
Questions about radon in Mountrail County
Are radon levels high in Mountrail County?
Over the 2008 to 2017 laboratory totals, 66.7% of the radon tests reported to CDC for Mountrail County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 7.3 pCi/L. Of 29 North Dakota counties with 30 or more tests for the same period, 12 reported a higher share; pooled, the state comes to 59.3%.
Which counties border Mountrail County?
Mountrail County borders 6 counties: Burke County, Ward County, Williams County, Dunn County, McKenzie County and McLean County.
Products
Mountrail County, Products
Testing a home in Mountrail County
In Mountrail County, 66.7% of 48 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 59.3% pooled across North Dakota. In Zone 1 the year-round level in Mountrail 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
Mountrail County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Mountrail County
Explore
Mountrail County, Bordering counties
Counties bordering Mountrail County
Calculated by Radon411- Radon levels in Dunn CountyEPA zone 1
74.3%at or above 4 pCi/L
Median 7.1 pCi/L · 35 tests · 7.6 points above Mountrail County
- Radon levels in Burke CountyEPA zone 1
63.6%at or above 4 pCi/L
Median 7.8 pCi/L · 11 tests · 3.1 points below Mountrail County
- Radon levels in McLean CountyEPA zone 1
63.2%at or above 4 pCi/L
Median 5.6 pCi/L · 95 tests · 3.5 points below Mountrail County
- Radon levels in McKenzie CountyEPA zone 1
56.1%at or above 4 pCi/L
Median 4.8 pCi/L · 41 tests · 10.6 points below Mountrail County
- Radon levels in Ward CountyEPA zone 1
43.0%at or above 4 pCi/L
Median 3.3 pCi/L · 446 tests · 23.7 points below Mountrail County
- Radon levels in Williams CountyEPA zone 1
33.8%at or above 4 pCi/L
Median 2.9 pCi/L · 204 tests · 32.9 points below Mountrail County
Mountrail County, Cities and towns
Cities and towns in Mountrail County
About 9,395 people live in Mountrail County by the Census Bureau's estimate for July 1, 2025, 413 fewer than in 2020 (−4.2%). Spread over its land, that is 5.1 people to the square mile. Its largest town, New Town, has 2,715 residents, 28.9% of the total. Together its 7 incorporated places hold 67.1% of those residents; the other 32.9% live outside any of them. Reported testing is thin here: 48 tests over 2008 to 2017, or 5.1 for every 1,000 residents (2025 estimate), where North Dakota as a whole comes to 8.3.
From New Town to White Earth, CDC publishes no figure by town: each reads Mountrail County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| New Town | 2,715 | −2.0% | 28.9% |
| Stanley | 2,181 | −7.9% | 23.2% |
| Parshall | 895 | −5.4% | 9.5% |
| Plaza | 204 | −3.3% | 2.2% |
| Palermo | 122 | −3.2% | 1.3% |
| Ross | 96 | +2.1% | 1.0% |
| White Earth | 92 | −7.1% | 1.0% |
7 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).
Mountrail County, Homes
Homes in Mountrail County
Of Mountrail County's 5,073 homes, 57% are detached houses, against 57% across North Dakota; 20% are mobile homes. Much of Mountrail County is recent building: 41% of its homes have gone up since 2000 and the middle year built is 1989, against 1981 for North Dakota. 60% of occupied homes are lived in by their owner (North Dakota: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Mountrail County | North Dakota |
|---|---|---|
| Housing units | 5,073 | 374,866 |
| Detached houses | 57% | 57% |
| In buildings of 5 or more | 12% | 25% |
| Mobile homes | 20% | 7% |
| Built before 1960 | 22% | 24% |
| Built since 2000 | 41% | 31% |
| Middle year built | 1989 | 1981 |
| Owner-occupied | 60% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.