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 Chouteau County, Montana
EPA puts Chouteau County in Zone 1, its highest radon zone, and only 11 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
Highest bordering
72.2%
Fergus County
- Fergus
- 72.2%
- Hill
- 35.0%
4 of 8 neighbours have 30+ tests, 2006 to 2015
Nearest county
35.0%
Hill County, 54 miles
- Hill
- 35.0%
- Montana
- 47.4%
Share at 4+ pCi/L, 120 tests, 2006 to 2015
Ground above low
100.0%
Level with Montana
- Chouteau
- 100.0%
- Montana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
14
Too few for a share
- Chouteau
- 14
- Needed
- 30
2005 to 2014, laboratory
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Read a result for Chouteau County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 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.
The data
Chouteau County, At a glance
Chouteau County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Chouteau County in
USGS geologic potential: High across 91% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Chouteau County, 2008 to 2017, laboratory
CDC holds 11 reported tests for Chouteau County over the 2008 to 2017 laboratory totals, with a median of 5.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Chouteau County beside the counties around it is how this page reads it.
What these figures count
Only 11 tests were reported to CDC for Chouteau 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).
Chouteau County, Compared
Chouteau County radon figures, compared
Calculated by Radon411CDC's largest figure for Chouteau County rests on 14 tests over the 2005 to 2014 laboratory totals, 8 of them at or above 4 pCi/L, so each test moves its share by 7.1 points and no rank or comparison is drawn from it. Results reached as high as 10.4 pCi/L, with a middle value of 5.1 pCi/L.
Of the counties bordering it, 4 have a figure over the 2006 to 2015 laboratory totals: Fergus County reported the largest share at or above 4 pCi/L, 72.2%, and Hill County the smallest, 35.0%, with Judith Basin County at 64.3% and Cascade County at 35.9% between. Farther out, Lewis and Clark County (105 miles away) at 63.5%, Jefferson County (143 miles away) at 66.1% and Stillwater County (161 miles away) at 61.8% have figures too. Pooled across 52 Montana counties, 47.4% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Sheridan County reported the highest share (75.7%) and Hill County the lowest (35.0%). EPA's 1993 map puts Chouteau County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 91% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Chouteau County, Geology
The ground under Chouteau County
PredictedMost of the ground under Chouteau County is one class on USGS's geologic map: 90.9% of its land is high radon potential, with 9.1% moderate. The map puts 83.9% of Chouteau County in the area it calls Great Plains (Glaciated) and 9.1% in Plains and Mountains, with one smaller area beside them. USGS gives the first a radon index of 13, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).
| 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 | 83.9% |
| Plains and Mountains | Marine and continental shale, siltstone, and sandstone of Cretaceous and Tertiary ages, and volcanic rocks. | Moderate | 10 | 9.1% |
| Northern Rocky Mountains | Granitic, metaigneous, metasedimentary rocks, valley fill colluvium and alluvium. | High | 13 | 7.0% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Chouteau County beside the ground around it
Chouteau County has more high-potential ground than Montana as a whole: 90.9% of its land against 78.5%. Of the 8 counties that border it, 6 have more high-potential ground, Blaine County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Chouteau County, Local resources
Radon testing and mitigation in Chouteau 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
Chouteau County, Questions
Questions about radon in Chouteau County
Are radon levels high in Chouteau County?
Over the 2008 to 2017 laboratory totals, 54.5% of the radon tests reported to CDC for Chouteau County, Montana were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.5 pCi/L. Of the counties bordering it, 4 have a figure over the 2006 to 2015 laboratory totals: Fergus County reported the largest share at or above 4 pCi/L, 72.2%, and Hill County the smallest, 35.0%, with Judith Basin County at 64.3% and Cascade County at 35.9% between.
Which counties border Chouteau County?
Chouteau County borders 8 counties: Hill County, Liberty County, Cascade County, Judith Basin County, Fergus County, Blaine County, Teton County and Pondera County.
Products
Chouteau County, Products
Testing a home in Chouteau County
No CDC figure names Chouteau County; the nearest county with one, Hill County (54 miles away), reported 35.0% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in Chouteau 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
EcoQube Wi-Fi continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi
- App only
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Chouteau County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Chouteau County
Explore
Chouteau County, Bordering counties
Counties bordering Chouteau County
Calculated by Radon411- Radon levels in Fergus CountyEPA zone 1
72.2%at or above 4 pCi/L
Median 7.0 pCi/L · 72 tests
- Radon levels in Judith Basin CountyEPA zone 1
64.3%at or above 4 pCi/L
Median 5.9 pCi/L · 42 tests
- Radon levels in Cascade CountyEPA zone 1
35.9%at or above 4 pCi/L
Median 2.6 pCi/L · 284 tests
- Radon levels in Hill CountyEPA zone 1
35.0%at or above 4 pCi/L
Median 3.2 pCi/L · 120 tests
- Radon levels in Liberty CountyEPA zone 1
33.3%at or above 4 pCi/L
Median 3.8 pCi/L · 3 tests
- Radon levels in Teton CountyEPA zone 1
22.2%at or above 4 pCi/L
Median 2.9 pCi/L · 9 tests
- Radon levels in Blaine CountyEPA zone 1
5.9%at or above 4 pCi/L
Median 1.3 pCi/L · 17 tests
- Radon levels in Pondera CountyEPA zone 1
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 5 tests
Chouteau County, Cities and towns
Cities and towns in Chouteau County
About 5,865 people live in Chouteau County by the Census Bureau's estimate for July 1, 2025, 46 fewer than in 2020 (−0.8%). Spread over its land, that is 1.5 people to the square mile. Its largest town, Fort Benton, has 1,416 residents, 24.1% of the total. Together its 3 incorporated places hold 37.8% of those residents; the other 62.2% live outside any of them. Reported testing is thin here: 14 tests over 2005 to 2014, or 2.4 for every 1,000 residents (2025 estimate), where Montana as a whole comes to 6.7.
From Fort Benton to Geraldine, CDC publishes no figure by town: each reads Chouteau County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Fort Benton | 1,416 | −2.6% | 24.1% |
| Big Sandy | 598 | −4.0% | 10.2% |
| Geraldine | 204 | −3.3% | 3.5% |
3 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).
Chouteau County, Homes
Homes in Chouteau County
Chouteau County is a place of houses on their own lots: 79% of its 2,868 homes are detached single-family houses, against 69% across Montana. The homes are older than Montana's as a whole: half were built before 1967 (1980 for Montana), and 45% date from before 1960. 66% 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 | Chouteau County | Montana |
|---|---|---|
| Housing units | 2,868 | 522,939 |
| Detached houses | 79% | 69% |
| In buildings of 5 or more | 4% | 9% |
| Mobile homes | 16% | 10% |
| Built before 1960 | 45% | 26% |
| Built since 2000 | 9% | 27% |
| Middle year built | 1967 | 1980 |
| Owner-occupied | 66% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.