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Radon Levels in Wells County, North Dakota

EPA puts Wells County in Zone 1, its highest radon zone, and high results are common there: 48.1% of the 81 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    48.1%

    11.2 pts below ND

    Wells
    48.1%
    ND
    59.3%

    81 tests, 2008 to 2017

  • Median result

    3.8pCi/L

    Below action level

    Wells
    3.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    81

    17th of 29 by tests

    Wells
    81
    Burleigh
    1,558

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in ND

    26 of 29

    Lowest quarter

    Wells
    48.1%
    Pembina
    82.5%

    By share, of 29 with 30+ tests

Read a result for Wells County

Starts at Wells County's median, 3.8 pCi/L

3.8pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 3.8 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 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. Wells County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Wells County, At a glance

Wells County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Wells County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

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 Wells County, 2008 to 2017, laboratory

Reported results by concentration band, Wells County, 2008 to 2017, laboratory
Under 2 pCi/L: 17%2 to 4 pCi/L: 35%4 pCi/L and above: 48%

Of 81 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Wells County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L1417.3%
2 to 4 pCi/L2834.6%
4 pCi/L and above3948.1%
What these figures count

These are the 81 tests reported to CDC for Wells 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).

How to read these figures

Wells County, Compared

Wells County radon figures, compared

Calculated by Radon411

In Wells County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (39 of 81) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 12.4 points higher. Across 53 North Dakota counties pooled together, 59.3% of tests reached that level, so Wells County runs 11.2 points below its state.

Of 4 neighbours with a figure, all 4 reported a larger share at or above 4 pCi/L; the spread is 48.7% (Pierce County) to 77.4% (Benson County). By share, Wells County is 26th of 29 North Dakota counties with 30 or more tests for the same period.

Half the tests came in under 3.8 pCi/L and half over it; the single highest reached 17.9 pCi/L. Below the action level, 14 tests (17.3%) came in under 2 pCi/L, against 18.3% statewide, and 28 tests (34.6%) fell between 2 and 4, against 22.4% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 48.1% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

CDC's ten-year totals for Wells County went from 110 tests (2005 to 2014) to 81 (2008 to 2017), the share going from 38.2% to 48.1%.

Wells County against North Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Wells County
Wells County8148.1%3.8 pCi/LThis county
North Dakota, pooled53 counties, pooled6,60759.3%Not pooled+11.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−12.4 points
Pembina Countyhighest in the state5782.5%9.3 pCi/L+34.4 points
Williams Countylowest in the state20433.8%2.9 pCi/L−14.3 points
Kidder County, NDborders it2979.3%7.3 pCi/L+31.2 points
Benson County, NDborders it3177.4%6.2 pCi/L+29.3 points
Stutsman County, NDborders it35173.5%5.8 pCi/L+25.4 points
Foster County, NDborders it3161.3%4.5 pCi/L+13.2 points
Sheridan County, NDborders it1154.5%4.2 pCi/L+6.4 points
Pierce County, NDborders it3948.7%3.8 pCi/L+0.6 points
Eddy County, NDborders it812.5%0.9 pCi/L−35.6 points
Where Wells County's reported results fell, 2008 to 2017, laboratory, beside North Dakota and the United States
ResultWells County testsWells County shareNorth Dakota shareU.S. shareAgainst North Dakota
Under 2 pCi/L1417.3%18.3%39.6%−1.0 points
2 to 4 pCi/L2834.6%22.4%24.7%+12.2 points
4 pCi/L and above3948.1%59.3%35.7%−11.2 points
Wells County ranked among the 29 North Dakota counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Foster County19 of 293161.3%4.5 pCi/L
Cass County20 of 2986257.5%4.7 pCi/L
McKenzie County21 of 294156.1%4.8 pCi/L
Morton County22 of 2926853.4%4.2 pCi/L
Traill County23 of 293751.4%4.1 pCi/L
Burleigh County24 of 291,55851.1%4.0 pCi/L
Pierce County25 of 293948.7%3.8 pCi/L
Wells County26 of 298148.1%3.8 pCi/L
Ward County27 of 2944643.0%3.3 pCi/L
Richland County28 of 299343.0%3.6 pCi/L
Williams County29 of 2920433.8%2.9 pCi/L
Wells County ten-year laboratory totals, against North Dakota's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestNorth Dakota, pooledChange from the row before
2008 to 20178148.1%3.8 pCi/L17.9 pCi/L59.3%+1.6 points
2007 to 201610146.5%3.7 pCi/L18.9 pCi/L58.7%+6.9 points
2006 to 201511139.6%3.3 pCi/L18.9 pCi/L56.3%+1.4 points
2005 to 201411038.2%3.3 pCi/L18.9 pCi/L54.0%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Wells County, Geology

The ground under Wells County

Predicted

USGS's geologic map puts all of Wells 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).

USGS's geologic areas under Wells County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Great Plains (Glaciated)Glacial deposits derived from Cretaceous shales containing higher than average amounts of uranium.High13100%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Wells County beside the ground around it

On high-potential ground Wells County is close to North Dakota as a whole: 100% of its land against 98.9%. Of the 7 counties that border it, none has as large a share of high-potential ground; Eddy County comes nearest at 100%.

Share of land by USGS radon potential: Wells County, the 7 counties bordering it and North Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Wells CountyZone 1NoneNone100%
Sheridan CountyZone 1NoneNone100%
Foster CountyZone 1NoneNone100%
Eddy CountyZone 1NoneNone100%
Kidder CountyZone 1NoneNone100%
Benson CountyZone 1NoneNone100%
Pierce CountyZone 1NoneNone100%
Stutsman CountyZone 1NoneNone100%
North Dakota53 counties, pooled by land areaVariesNone1.1%98.9%

The map rates the ground, not the air in any home.

Local help

Wells County, Local resources

Radon testing and mitigation in Wells County

What North Dakota's program says
Phone
701-328-5166
Email
jOtto@nd.gov

What it means

Wells County, Questions

Questions about radon in Wells County

Are radon levels high in Wells County?

Over the 2008 to 2017 laboratory totals, 48.1% of the radon tests reported to CDC for Wells County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.8 pCi/L. Of 29 North Dakota counties with 30 or more tests for the same period, 25 reported a higher share; pooled, the state comes to 59.3%.

Which counties border Wells County?

Wells County borders 7 counties: Sheridan County, Foster County, Eddy County, Kidder County, Benson County, Pierce County and Stutsman County.

Products

Wells County, Products

Testing a home in Wells County

In Wells County, 48.1% of 81 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 Wells 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

Wells County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Wells County

Explore

Wells County, Bordering counties

Counties bordering Wells County

Calculated by Radon411

Wells County, Cities and towns

Cities and towns in Wells County

Wells County has been losing residents: from 3,963 in 2020 to 3,729 on July 1, 2025, a fall of 5.9% by the Census Bureau's estimates. Spread over its land, that is 2.9 people to the square mile. Its largest town, Harvey, has 1,532 residents, 41.1% of the total. Together its 7 incorporated places hold 61.2% of those residents; the other 38.8% live outside any of them. Testing is reported here more often than across the state: CDC's 81 reported tests for 2008 to 2017 come to 21.7 for every 1,000 residents (2025 estimate), against 8.3 for North Dakota.

From Harvey to Hamberg, CDC publishes no figure by town: each reads Wells County's.

The cities and towns in Wells County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Harvey1,532−6.3%41.1%
Fessenden437−5.2%11.7%
Bowdon131−4.4%3.5%
Sykeston95−6.9%2.5%
Hurdsfield58−7.9%1.6%
Cathay19−5.0%0.5%
Hamberg12−7.7%0.3%

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).

Wells County, Homes

Homes in Wells County

Wells County is a place of houses on their own lots: 79% of its 2,250 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 1962 (1981 for North Dakota), and 46% date from before 1960. 74% 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 in Wells County, North Dakota, 2019 to 2023
HomesWells CountyNorth Dakota
Housing units2,250374,866
Detached houses79%57%
In buildings of 5 or more9%25%
Mobile homes4%7%
Built before 196046%24%
Built since 20006%31%
Middle year built19621981
Owner-occupied74%63%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.