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Radon Levels in Benson County, North Dakota

EPA puts Benson County in Zone 1, its highest radon zone, and high results are common there: 77.4% of the 31 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

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  • Share at 4+ pCi/L

    77.4%

    18.1 pts above ND

    Benson
    77.4%
    ND
    59.3%

    31 tests, 2008 to 2017

  • Median result

    6.2pCi/L

    Action level reached

    Benson
    6.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    31

    28th of 29 by tests

    Benson
    31
    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

    3 of 29

    Top quarter

    Benson
    77.4%
    Pembina
    82.5%

    By share, of 29 with 30+ tests

Read a result for Benson County

Starts at Benson County's median, 6.2 pCi/L

6.2pCi/L

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

EPA’s reading of 6.2 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Benson County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Benson County, At a glance

Benson County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Benson 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 Benson County, 2008 to 2017, laboratory

Reported results by concentration band, Benson County, 2008 to 2017, laboratory
Under 2 pCi/L: 10%2 to 4 pCi/L: 13%4 pCi/L and above: 77%

Of 31 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Benson County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L39.7%
2 to 4 pCi/L412.9%
4 pCi/L and above2477.4%
What these figures count

These are the 31 tests reported to CDC for Benson 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

Benson County, Compared

Benson County radon figures, compared

Calculated by Radon411

More than half: 77.4% of the 31 radon tests reported to CDC for Benson County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 3rd of 29 North Dakota counties with 30 or more tests for the same period. That is 18.1 points above the 59.3% pooled from 53 North Dakota counties.

The median result, 6.2 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 14.4 pCi/L. The rest split 9.7% under 2 pCi/L and 12.9% 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 77.4% share point the same way here.

No bordering county with a figure for the same period reported a higher share; the closest is Ramsey County at 76.9%, the lowest Wells County at 48.1%. 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 Benson County went from 41 tests (2005 to 2014) to 31 (2008 to 2017), the share going from 65.9% to 77.4%.

Nationally, every county with a figure for the same period pools to 35.7%; Benson County sits 41.7 points above it.

Benson County against North Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Benson County
Benson County3177.4%6.2 pCi/LThis county
North Dakota, pooled53 counties, pooled6,60759.3%Not pooled−18.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−41.7 points
Pembina Countyhighest in the state5782.5%9.3 pCi/L+5.1 points
Williams Countylowest in the state20433.8%2.9 pCi/L−43.6 points
Ramsey County, NDborders it13476.9%6.9 pCi/L−0.5 points
Nelson County, NDborders it1963.2%5.7 pCi/L−14.2 points
Towner County, NDborders it2556.0%5.6 pCi/L−21.4 points
Pierce County, NDborders it3948.7%3.8 pCi/L−28.7 points
Wells County, NDborders it8148.1%3.8 pCi/L−29.3 points
Eddy County, NDborders it812.5%0.9 pCi/L−64.9 points
Where Benson County's reported results fell, 2008 to 2017, laboratory, beside North Dakota and the United States
ResultBenson County testsBenson County shareNorth Dakota shareU.S. shareAgainst North Dakota
Under 2 pCi/L39.7%18.3%39.6%−8.6 points
2 to 4 pCi/L412.9%22.4%24.7%−9.5 points
4 pCi/L and above2477.4%59.3%35.7%+18.1 points
Benson 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
Pembina County1 of 295782.5%9.3 pCi/L
Walsh County2 of 2913279.5%9.8 pCi/L
Benson County3 of 293177.4%6.2 pCi/L
Ramsey County4 of 2913476.9%6.9 pCi/L
Grand Forks County5 of 2968075.9%8.8 pCi/L
Dunn County6 of 293574.3%7.1 pCi/L
Stutsman County7 of 2935173.5%5.8 pCi/L
McIntosh County8 of 293271.9%7.0 pCi/L
Bowman County9 of 293571.4%5.8 pCi/L
LaMoure County10 of 294470.5%5.2 pCi/L
Barnes County11 of 298367.5%5.6 pCi/L
Benson 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 20173177.4%6.2 pCi/L14.4 pCi/L59.3%+1.5 points
2007 to 20162975.9%5.7 pCi/L11.7 pCi/L58.7%−3.5 points
2006 to 20153479.4%6.3 pCi/L11.7 pCi/L56.3%+13.5 points
2005 to 20144165.9%5.2 pCi/L11.7 pCi/L54.0%First on file

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

Benson County, Geology

The ground under Benson County

Predicted

USGS's geologic map puts all of Benson County's mapped land in one class: high radon potential. The map puts 93.8% of Benson County in the area it calls Great Plains (Glaciated) and 5.7% in Glacial Lakes. USGS gives the first a radon index of 13 and the second 14, both in the high band (12 to 17).

USGS's geologic areas under Benson 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.High1393.8%
Glacial LakesSilt and clay lake deposits derived from Cretaceous shales containing higher than average amounts of uranium.High145.7%

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

Benson County beside the ground around it

On high-potential ground Benson County is close to North Dakota as a whole: 100% of its land against 98.9%. Of the 6 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: Benson County, the 6 counties bordering it and North Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Benson CountyZone 1NoneNone100%
Pierce CountyZone 1NoneNone100%
Ramsey CountyZone 1NoneNone100%
Eddy CountyZone 1NoneNone100%
Towner CountyZone 1NoneNone100%
Wells CountyZone 1NoneNone100%
Nelson 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

Benson County, Local resources

Radon testing and mitigation in Benson County

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

What it means

Benson County, Questions

Questions about radon in Benson County

Are radon levels high in Benson County?

Over the 2008 to 2017 laboratory totals, 77.4% of the radon tests reported to CDC for Benson County, North Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.2 pCi/L. Of 29 North Dakota counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 59.3%.

Which counties border Benson County?

Benson County borders 6 counties: Pierce County, Ramsey County, Eddy County, Towner County, Wells County and Nelson County.

Products

Benson County, Products

Testing a home in Benson County

In Benson County, 77.4% of 31 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 Benson 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

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

Explore

Benson County, Bordering counties

Counties bordering Benson County

Calculated by Radon411

Benson County, Cities and towns

Cities and towns in Benson County

About 5,759 people live in Benson County by the Census Bureau's estimate for July 1, 2025, 181 fewer than in 2020 (−3.0%). Spread over its land, that is 4.1 people to the square mile. No town dominates: Leeds, the largest, has 424 residents, 7.4% of the total. Together its 9 incorporated places hold 22.5% of those residents; the other 77.5% live outside any of them. Reported testing is thin here: 31 tests over 2008 to 2017, or 5.4 for every 1,000 residents (2025 estimate), where North Dakota as a whole comes to 8.3.

From Leeds to York, CDC publishes no figure by town: each reads Benson County's.

The cities and towns in Benson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Leeds424−3.6%7.4%
Maddock384−3.8%6.7%
Minnewaukan190−1.6%3.3%
Oberon93−3.1%1.6%
Esmond91−2.2%1.6%
Warwick51−3.8%0.9%
Brinsmade28−3.4%0.5%
Knox20−4.8%0.3%
York14−6.7%0.2%

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).

Benson County, Homes

Homes in Benson County

Of Benson County's 2,544 homes, 73% are detached houses, against 57% across North Dakota; 16% are mobile homes. The homes are older than North Dakota's as a whole: half were built before 1970 (1981 for North Dakota), and 30% 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 Benson County, North Dakota, 2019 to 2023
HomesBenson CountyNorth Dakota
Housing units2,544374,866
Detached houses73%57%
In buildings of 5 or more5%25%
Mobile homes16%7%
Built before 196030%24%
Built since 200011%31%
Middle year built19701981
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.