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 Traill County, North Dakota
EPA puts Traill County in Zone 1, its highest radon zone, and high results are common there: 51.4% of the 37 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
51.4%
7.9 pts below ND
- Traill
- 51.4%
- ND
- 59.3%
37 tests, 2008 to 2017
Median result
4.1pCi/L
Action level reached
- Traill
- 4.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
37
24th of 29 by tests
- Traill
- 37
- 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
23 of 29
Lowest quarter
- Traill
- 51.4%
- Pembina
- 82.5%
By share, of 29 with 30+ tests
Read a result for Traill County
Starts at Traill County's median, 4.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.1 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. Traill County's median reported result, 2008 to 2017.
The data
Traill County, At a glance
Traill County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Traill 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 Traill County, 2008 to 2017, laboratory
Under 2 pCi/L: 24%2 to 4 pCi/L: 24%4 pCi/L and above: 52%
Of 37 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 9 | 24.3% |
| 2 to 4 pCi/L | 9 | 24.3% |
| 4 pCi/L and above | 19 | 51.4% |
What these figures count
These are the 37 tests reported to CDC for Traill 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).
Traill County, Compared
Traill County radon figures, compared
Calculated by Radon411More than half: 51.4% of the 37 radon tests reported to CDC for Traill County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 23rd of 29 North Dakota counties with 30 or more tests for the same period. That is 7.9 points below the 59.3% pooled from 53 North Dakota counties.
The median result, 4.1 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 27.6 pCi/L. The rest split 24.3% under 2 pCi/L and 24.3% 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 51.4% share point the same way here.
All 4 of its bordering counties with figures ran higher, led by Grand Forks County at 75.9%; the lowest of them, Cass County, reported 57.5%. 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 Traill County went from 45 tests (2005 to 2014) to 37 (2008 to 2017), the share going from 42.2% to 51.4%.
Nationally, every county with a figure for the same period pools to 35.7%; Traill County sits 15.7 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Traill County, Geology
The ground under Traill County
PredictedUSGS's geologic map puts all of Traill County's mapped land in one class: high radon potential. All of it lies in the area the map calls Glacial Lakes, to which USGS gives a radon index of 14, 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 of Glacial Lake Agassiz derived from Cretaceous shales containing higher than average amounts of uranium. | High | 14 | 99.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Traill County beside the ground around it
On high-potential ground Traill 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; Grand Forks County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Traill County, Local resources
Radon testing and mitigation in Traill 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
Traill County, Questions
Questions about radon in Traill County
Are radon levels high in Traill County?
Over the 2008 to 2017 laboratory totals, 51.4% of the radon tests reported to CDC for Traill County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.1 pCi/L. Of 29 North Dakota counties with 30 or more tests for the same period, 22 reported a higher share; pooled, the state comes to 59.3%.
Which counties border Traill County?
Traill County borders 5 counties: Steele County, ND, Polk County, MN, Norman County, MN, Cass County, ND and Grand Forks County, ND.
Products
Traill County, Products
Testing a home in Traill County
In Traill County, 51.4% of 37 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 Traill 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
Traill County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Traill County
Explore
Traill County, Bordering counties
Counties bordering Traill County
Calculated by Radon411- Radon levels in Grand Forks County, NDEPA zone 1
75.9%at or above 4 pCi/L
Median 8.8 pCi/L · 680 tests · 24.5 points above Traill County
- Radon levels in Polk County, MNEPA zone 1
70.8%at or above 4 pCi/L
Median 6.7 pCi/L · 397 tests · 19.4 points above Traill County
- Radon levels in Norman County, MNEPA zone 1
58.4%at or above 4 pCi/L
Median 4.8 pCi/L · 154 tests · 7.0 points above Traill County
- Radon levels in Cass County, NDEPA zone 1
57.5%at or above 4 pCi/L
Median 4.7 pCi/L · 862 tests · 6.1 points above Traill County
- Radon levels in Steele County, NDEPA zone 1
0.0%at or above 4 pCi/L
Median 2.0 pCi/L · 1 test · 51.4 points below Traill County
Traill County, Cities and towns
Cities and towns in Traill County
About 7,920 people live in Traill County by the Census Bureau's estimate for July 1, 2025, 64 fewer than in 2020 (−0.8%). Spread over its land, that is 9.2 people to the square mile. Its largest town, Mayville, has 1,807 residents, 22.8% of the total. Reported testing is thin here: 37 tests over 2008 to 2017, or 4.7 for every 1,000 residents (2025 estimate), where North Dakota as a whole comes to 8.3.
From Mayville to Clifford, CDC publishes no figure by town: each reads Traill County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Mayville | 1,807 | −2.3% | 22.8% |
| Hillsboro | 1,648 | Level | 20.8% |
| Hatton | 708 | −1.0% | 8.9% |
| Portland | 576 | −1.2% | 7.3% |
| Buxton | 349 | +0.3% | 4.4% |
| Reynoldsextends beyond Traill County | 273 | +1.5% | Counted whole |
| Grandinextends beyond Traill County | 191 | +3.2% | Counted whole |
| Galesburg | 112 | −2.6% | 1.4% |
| Clifford | 31 | Level | 0.4% |
9 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). A place that extends beyond Traill County is counted whole, so it has no share.
Traill County, Homes
Homes in Traill County
Traill County is a place of houses on their own lots: 76% of its 3,656 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 46% date from before 1960. 75% 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 | Traill County | North Dakota |
|---|---|---|
| Housing units | 3,656 | 374,866 |
| Detached houses | 76% | 57% |
| In buildings of 5 or more | 13% | 25% |
| Mobile homes | 3% | 7% |
| Built before 1960 | 46% | 24% |
| Built since 2000 | 13% | 31% |
| Middle year built | 1965 | 1981 |
| Owner-occupied | 75% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.