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Radon Levels in Pierce County, North Dakota

EPA puts Pierce County in Zone 1, its highest radon zone, and high results are common there: 48.7% of the 39 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

    48.7%

    10.6 pts below ND

    Pierce
    48.7%
    ND
    59.3%

    39 tests, 2008 to 2017

  • Median result

    3.8pCi/L

    Below action level

    Pierce
    3.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    39

    23rd of 29 by tests

    Pierce
    39
    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

    25 of 29

    Lowest quarter

    Pierce
    48.7%
    Pembina
    82.5%

    By share, of 29 with 30+ tests

Read a result for Pierce County

Starts at Pierce 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. Pierce County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Pierce County, At a glance

Pierce County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Pierce County, 2008 to 2017, laboratory
Under 2 pCi/L: 18%2 to 4 pCi/L: 33%4 pCi/L and above: 49%

Of 39 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Pierce County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L717.9%
2 to 4 pCi/L1333.3%
4 pCi/L and above1948.7%
What these figures count

These are the 39 tests reported to CDC for Pierce 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

Pierce County, Compared

Pierce County radon figures, compared

Calculated by Radon411

In Pierce County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (19 of 39) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 13.0 points higher. Across 53 North Dakota counties pooled together, 59.3% of tests reached that level, so Pierce County runs 10.6 points below its state.

Of 3 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 48.1% (Wells County) to 77.4% (Benson County). By share, Pierce County is 25th 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 24.0 pCi/L. Below the action level, 7 tests (17.9%) came in under 2 pCi/L, against 18.3% statewide, and 13 tests (33.3%) fell between 2 and 4, against 22.4% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 48.7% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

CDC's ten-year totals for Pierce County went from 42 tests (2005 to 2014) to 39 (2008 to 2017), the share going from 42.9% to 48.7%.

Pierce County against North Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Pierce County
Pierce County3948.7%3.8 pCi/LThis county
North Dakota, pooled53 counties, pooled6,60759.3%Not pooled+10.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−13.0 points
Pembina Countyhighest in the state5782.5%9.3 pCi/L+33.8 points
Williams Countylowest in the state20433.8%2.9 pCi/L−14.9 points
Benson County, NDborders it3177.4%6.2 pCi/L+28.7 points
McHenry County, NDborders it2864.3%5.3 pCi/L+15.6 points
Bottineau County, NDborders it11164.0%5.7 pCi/L+15.3 points
Towner County, NDborders it2556.0%5.6 pCi/L+7.3 points
Sheridan County, NDborders it1154.5%4.2 pCi/L+5.8 points
Wells County, NDborders it8148.1%3.8 pCi/L−0.6 points
Rolette County, NDborders it2646.2%3.4 pCi/L−2.5 points
Where Pierce County's reported results fell, 2008 to 2017, laboratory, beside North Dakota and the United States
ResultPierce County testsPierce County shareNorth Dakota shareU.S. shareAgainst North Dakota
Under 2 pCi/L717.9%18.3%39.6%−0.4 points
2 to 4 pCi/L1333.3%22.4%24.7%+10.9 points
4 pCi/L and above1948.7%59.3%35.7%−10.6 points
Pierce 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
Pierce 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 20173948.7%3.8 pCi/L24.0 pCi/L59.3%+2.5 points
2007 to 20163946.2%3.8 pCi/L24.0 pCi/L58.7%+1.2 points
2006 to 20154045.0%3.8 pCi/L24.0 pCi/L56.3%+2.1 points
2005 to 20144242.9%3.7 pCi/L24.0 pCi/L54.0%First on file

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

Pierce County, Geology

The ground under Pierce County

Predicted

USGS's geologic map puts all of Pierce County's mapped land in one class: high radon potential. The map puts 83.8% of Pierce County in the area it calls Great Plains (Glaciated) and 16.2% 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 Pierce 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.High1383.8%
Glacial LakesSilt and clay deposits derived from Cretaceous shales containing higher than average amounts of uranium.High1416.2%

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

Pierce County beside the ground around it

On high-potential ground Pierce 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; McHenry County comes nearest at 100%.

Share of land by USGS radon potential: Pierce County, the 7 counties bordering it and North Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Pierce CountyZone 1NoneNone100%
Benson CountyZone 1NoneNone100%
McHenry CountyZone 1NoneNone100%
Rolette CountyZone 1NoneNone100%
Towner CountyZone 1NoneNone100%
Sheridan CountyZone 1NoneNone100%
Wells CountyZone 1NoneNone100%
Bottineau 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

Pierce County, Local resources

Radon testing and mitigation in Pierce County

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

What it means

Pierce County, Questions

Questions about radon in Pierce County

Are radon levels high in Pierce County?

Over the 2008 to 2017 laboratory totals, 48.7% of the radon tests reported to CDC for Pierce 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, 24 reported a higher share; pooled, the state comes to 59.3%.

Which counties border Pierce County?

Pierce County borders 7 counties: Benson County, McHenry County, Rolette County, Towner County, Sheridan County, Wells County and Bottineau County.

Products

Pierce County, Products

Testing a home in Pierce County

In Pierce County, 48.7% of 39 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 Pierce 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

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

Explore

Pierce County, Bordering counties

Counties bordering Pierce County

Calculated by Radon411

Pierce County, Cities and towns

Cities and towns in Pierce County

About 3,838 people live in Pierce County by the Census Bureau's estimate for July 1, 2025, 143 fewer than in 2020 (−3.6%). Spread over its land, that is 3.8 people to the square mile. Rugby alone is home to 2,412 of them, 62.8% of the total. Together its 3 incorporated places hold 65.6% of those residents; the other 34.4% live outside any of them. CDC's 39 reported tests for 2008 to 2017 work out to 10.2 per 1,000 residents (2025 estimate), close to North Dakota's 8.3.

From Rugby to Wolford, CDC publishes no figure by town: each reads Pierce County's.

The cities and towns in Pierce County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Rugby2,412−3.5%62.8%
Balta63−4.5%1.6%
Wolford42−4.5%1.1%

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).

Pierce County, Homes

Homes in Pierce County

Pierce County is a place of houses on their own lots: 82% of its 2,077 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 1971 (1981 for North Dakota), and 40% date from before 1960. Owners live in 79% of the occupied homes (North Dakota: 63%), so for most households a test and a fix are their own to order.

Homes in Pierce County, North Dakota, 2019 to 2023
HomesPierce CountyNorth Dakota
Housing units2,077374,866
Detached houses82%57%
In buildings of 5 or more4%25%
Mobile homes5%7%
Built before 196040%24%
Built since 200011%31%
Middle year built19711981
Owner-occupied79%63%

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