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 Billings County, North Dakota
EPA puts Billings County in Zone 1, its highest radon zone, and only 20 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
90.9%
36.9 pts above ND
- Billings
- 90.9%
- ND
- 54.0%
33 tests, 2005 to 2014
Median result
11.8pCi/L
Action level reached
- Billings
- 11.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2005 to 2014
Tests reported
33
37th of 39 by tests
- Billings
- 33
- Burleigh
- 1,312
Reported to CDC before any fix, 2005 to 2014
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
1 of 39
Top quarter
- Billings
- 90.9%
- Billings
- 90.9%
By share, of 39 with 30+ tests
Read a result for Billings County
Starts at Billings County's median, 11.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 11.8 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. Billings County's median reported result, 2005 to 2014.
The data
Billings County, At a glance
Billings County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Billings 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 Billings County, 2008 to 2017, laboratory
CDC holds 20 reported tests for Billings County over the 2008 to 2017 laboratory totals, with a median of 11.0 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Billings County beside the counties around it is how this page reads it.
What these figures count
Only 20 tests were reported to CDC for Billings 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).
Billings County, Compared
Billings County radon figures, compared
Calculated by Radon411More than half: 90.9% of the 33 radon tests reported to CDC for Billings County over the 2005 to 2014 laboratory totals read at least 4 pCi/L. That places it 1st of 39 North Dakota counties with 30 or more tests for the same period. That is 36.9 points above the 54.0% pooled from 53 North Dakota counties.
The newest figure, over the 2008 to 2017 laboratory totals, counts only 20 tests (85.0% at or above 4 pCi/L), too few to compare, so this reading uses the 33-test figure.
The median result, 11.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 93.9 pCi/L. The rest split 9.1% under 2 pCi/L and 0.0% from 2 to 4 (North Dakota: 22.0% and 23.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 90.9% share point the same way here.
No bordering county with a figure for the same period reported a higher share; the closest is Dunn County at 77.8%, the lowest McKenzie County at 62.0%. Statewide for the same period, Dunn County reported the highest share (77.8%) and Williams County the lowest (35.1%).
CDC's ten-year totals for Billings County went from 33 tests (2005 to 2014) to 20 (2008 to 2017), the share going from 90.9% to 85.0%.
Nationally, every county with a figure for the same period pools to 36.0%; Billings County sits 54.9 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Billings County, Geology
The ground under Billings County
PredictedUSGS's geologic map puts all of Billings County's mapped land in one class: high radon potential. All of it lies in the area the map calls Great Plains (Unglaciated), 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 (Unglaciated) | Tertiary and Upper Cretaceous sandstones, shales, and locally, coal-bearing units. | 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.
Billings County beside the ground around it
On high-potential ground Billings County is close to North Dakota as a whole: 100% of its land against 98.9%. Of the 5 counties that border it, none has as large a share of high-potential ground; Golden Valley County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Billings County, Local resources
Radon testing and mitigation in Billings 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
Billings County, Questions
Questions about radon in Billings County
Are radon levels high in Billings County?
Over the 2008 to 2017 laboratory totals, 85.0% of the radon tests reported to CDC for Billings County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 11.0 pCi/L. Of 39 North Dakota counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 54.0%.
Which counties border Billings County?
Billings County borders 5 counties: Golden Valley County, Slope County, Stark County, Dunn County and McKenzie County.
Products
Billings County, Products
Testing a home in Billings County
In Billings County, 90.9% of 33 tests reported to CDC over the 2005 to 2014 laboratory totals reached 4 pCi/L, against 54.0% pooled across North Dakota. In Zone 1 the year-round level in Billings 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
MonitorAEGTEST
HOUND-1011S rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Billings County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Billings County
Explore
Billings County, Bordering counties
Counties bordering Billings County
Calculated by Radon411- Radon levels in Dunn CountyEPA zone 1
77.8%at or above 4 pCi/L
Median 6.9 pCi/L · 54 tests · 13.1 points below Billings County
- Radon levels in Slope CountyEPA zone 1
76.5%at or above 4 pCi/L
Median 16.0 pCi/L · 17 tests · 14.4 points below Billings County
- Radon levels in Stark CountyEPA zone 1
62.2%at or above 4 pCi/L
Median 5.1 pCi/L · 405 tests · 28.7 points below Billings County
- Radon levels in McKenzie CountyEPA zone 1
62.0%at or above 4 pCi/L
Median 4.9 pCi/L · 50 tests · 28.9 points below Billings County
- Radon levels in Golden Valley CountyEPA zone 1
31.6%at or above 4 pCi/L
Median 2.7 pCi/L · 19 tests · 59.3 points below Billings County
Billings County, Cities and towns
Cities and towns in Billings County
Billings County is growing: the Census Bureau puts it at 1,071 residents on July 1, 2025, up 15.2% from 930 in 2020. Spread over its land, that is 0.9 people to the square mile. Medora, its one incorporated place, has 157 residents, 14.7% of the total. Testing is reported here more often than across the state: CDC's 33 reported tests for 2005 to 2014 come to 30.8 for every 1,000 residents (2025 estimate), against 8.2 for North Dakota.
Medora is the one incorporated place here; CDC publishes no figure by town, so it reads Billings County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Medora | 157 | +38.9% | 14.7% |
One incorporated place, 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).
Billings County, Homes
Homes in Billings County
Billings County is a place of houses on their own lots: 78% of its 527 homes are detached single-family houses, against 57% across North Dakota. Half of its homes were built before 1984, close to North Dakota's 1981: 22% date from before 1960 and 31% from 2000 or later. Owners live in 81% of the occupied homes (North Dakota: 63%), so for most households a test and a fix are their own to order.
| Homes | Billings County | North Dakota |
|---|---|---|
| Housing units | 527 | 374,866 |
| Detached houses | 78% | 57% |
| In buildings of 5 or more | 6% | 25% |
| Mobile homes | 12% | 7% |
| Built before 1960 | 22% | 24% |
| Built since 2000 | 31% | 31% |
| Middle year built | 1984 | 1981 |
| Owner-occupied | 81% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.