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 Dawson County, Montana
EPA puts Dawson County in Zone 1, its highest radon zone, and high results are common there: 47.5% of the 59 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
47.5%
2.0 pts above MT
- Dawson
- 47.5%
- Montana
- 45.5%
59 tests, 2008 to 2017
Median result
3.5pCi/L
Below action level
- Dawson
- 3.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
59
16th of 23 by tests
- Dawson
- 59
- Missoula
- 2,613
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 Montana
16 of 23
Middle half
- Dawson
- 47.5%
- Richland
- 78.6%
By share, of 23 with 30+ tests
Read a result for Dawson County
Starts at Dawson 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. Dawson County's median reported result, 2008 to 2017.
The data
Dawson County, At a glance
Dawson County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Dawson County in
USGS geologic potential: High across 87% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Dawson County, 2008 to 2017, laboratory
Under 2 pCi/L: 24%2 to 4 pCi/L: 29%4 pCi/L and above: 47%
Of 59 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 14 | 23.7% |
| 2 to 4 pCi/L | 17 | 28.8% |
| 4 pCi/L and above | 28 | 47.5% |
What these figures count
These are the 59 tests reported to CDC for Dawson 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).
Dawson County, Compared
Dawson County radon figures, compared
Calculated by Radon411In Dawson County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (28 of 59) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 11.8 points higher. Across 51 Montana counties pooled together, 45.5% of tests reached that level, so Dawson County runs 2.0 points above its state.
Richland County, the one bordering county with a figure for the same period, reported 78.6%. By share, Dawson County is 16th of 23 Montana counties with 30 or more tests for the same period.
Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 63.0 pCi/L. Below the action level, 14 tests (23.7%) came in under 2 pCi/L, against 29.2% statewide, and 17 tests (28.8%) fell between 2 and 4, against 25.2% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 47.5% share point the same way here. USGS geology rates 87% of the county's land high radon potential.
CDC's ten-year totals for Dawson County went from 52 tests (2005 to 2014) to 59 (2008 to 2017), the share going from 48.1% to 47.5%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Dawson County, Geology
The ground under Dawson County
PredictedMost of the ground under Dawson County is one class on USGS's geologic map: 87.0% of its land is high radon potential, with 13.0% moderate. The map puts 76.7% of Dawson County in the area it calls Great Plains and 13.0% in Eastern Great Plains, with one smaller area beside them. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Great Plains | Tertiary sandstone, siltstone, shale, coal. | High | 12 | 76.7% |
| Eastern Great Plains | Cretaceous marine shale and marine and nearshore sandstone, siltstone. | Moderate | 11 | 13.0% |
| Great Plains (Glaciated) | Glacial deposits derived from Cretaceous shales containing higher than average amounts of uranium. | High | 13 | 10.4% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Dawson County beside the ground around it
On high-potential ground Dawson County is close to Montana as a whole: 87.0% of its land against 78.5%. Of the 4 counties that border it, 3 have more high-potential ground, Richland County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Dawson County, Local resources
Radon testing and mitigation in Dawson County
- Radon Control ProgramRadon Control Program, run by Montana DEQ, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Montana.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Energy Bureau staff manage the radon information toll-free hotline and distribute subsidized radon test kits to Montana residents.
- Compare kits
- See the Montana directoryNo professionals are listed in Montana yet. The state program can point you to registered testers and mitigators.
What Montana's program says
- Phone
- 1-800-546-0483
- Licensing of radon professionals
Montana DEQ does not certify or require proof of certification for the contractors listed.
What it means
Dawson County, Questions
Questions about radon in Dawson County
Are radon levels high in Dawson County?
Over the 2008 to 2017 laboratory totals, 47.5% of the radon tests reported to CDC for Dawson County, Montana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 23 Montana counties with 30 or more tests for the same period, 15 reported a higher share; pooled, the state comes to 45.5%.
Which counties border Dawson County?
Dawson County borders 4 counties: Richland County, Prairie County, Wibaux County and McCone County.
Products
Dawson County, Products
Testing a home in Dawson County
In Dawson County, 47.5% of 59 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 45.5% pooled across Montana. In Zone 1 the year-round level in Dawson 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
Dawson County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Dawson County
Explore
Dawson County, Bordering counties
Counties bordering Dawson County
Calculated by Radon411- Radon levels in Richland CountyEPA zone 1
78.6%at or above 4 pCi/L
Median 5.9 pCi/L · 42 tests · 31.1 points above Dawson County
- Radon levels in Prairie CountyEPA zone 1
66.7%at or above 4 pCi/L
Median 7.6 pCi/L · 3 tests · 19.2 points above Dawson County
- Radon levels in Wibaux CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 3.0 pCi/L · 4 tests · 2.5 points above Dawson County
- Radon levels in McCone CountyEPA zone 1
0.0%at or above 4 pCi/L
Median 1.5 pCi/L · 1 test · 47.5 points below Dawson County
Dawson County, Cities and towns
Cities and towns in Dawson County
About 8,692 people live in Dawson County by the Census Bureau's estimate for July 1, 2025, 229 fewer than in 2020 (−2.6%). Spread over its land, that is 3.7 people to the square mile. Glendive alone is home to 4,736 of them, 54.5% of the total. Together its 2 incorporated places hold 56.3% of those residents; the other 43.7% live outside any of them. CDC's 59 reported tests for 2008 to 2017 work out to 6.8 per 1,000 residents (2025 estimate), close to Montana's 8.6.
From Glendive to Richey, CDC publishes no figure by town: each reads Dawson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Glendive | 4,736 | −2.7% | 54.5% |
| Richey | 160 | −3.0% | 1.8% |
2 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).
Dawson County, Homes
Homes in Dawson County
Dawson County is a place of houses on their own lots: 76% of its 4,377 homes are detached single-family houses, against 69% across Montana. The homes are older than Montana's as a whole: half were built before 1970 (1980 for Montana), and 38% date from before 1960. 72% of occupied homes are lived in by their owner (Montana: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Dawson County | Montana |
|---|---|---|
| Housing units | 4,377 | 522,939 |
| Detached houses | 76% | 69% |
| In buildings of 5 or more | 6% | 9% |
| Mobile homes | 11% | 10% |
| Built before 1960 | 38% | 26% |
| Built since 2000 | 9% | 27% |
| Middle year built | 1970 | 1980 |
| Owner-occupied | 72% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.