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Radon Levels in Kingsbury County, South Dakota

EPA puts Kingsbury County in Zone 1, its highest radon zone, and high results are common there: 68.2% of the 44 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

    68.2%

    9.7 pts above SD

    Kingsbury
    68.2%
    SD
    58.5%

    44 tests, 2008 to 2017

  • Median result

    7.4pCi/L

    Action level reached

    Kingsbury
    7.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    44

    20th of 23 by tests

    Kingsbury
    44
    Minnehaha
    1,920

    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 SD

    7 of 23

    Middle half

    Kingsbury
    68.2%
    Lake
    76.0%

    By share, of 23 with 30+ tests

Read a result for Kingsbury County

Starts at Kingsbury County's median, 7.4 pCi/L

7.4pCi/L

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

EPA’s reading of 7.4 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. Kingsbury County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Kingsbury County, At a glance

Kingsbury County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Kingsbury County, 2008 to 2017, laboratory
Under 2 pCi/L: 18%2 to 4 pCi/L: 14%4 pCi/L and above: 68%

Of 44 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Kingsbury County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L818.2%
2 to 4 pCi/L613.6%
4 pCi/L and above3068.2%
What these figures count

These are the 44 tests reported to CDC for Kingsbury 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

Kingsbury County, Compared

Kingsbury County radon figures, compared

Calculated by Radon411

More than half: 68.2% of the 44 radon tests reported to CDC for Kingsbury County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 7th of 23 South Dakota counties with 30 or more tests for the same period. That is 9.7 points above the 58.5% pooled from 62 South Dakota counties.

The median result, 7.4 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 24.7 pCi/L. The rest split 18.2% under 2 pCi/L and 13.6% from 2 to 4 (South Dakota: 23.6% and 17.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 68.2% share point the same way here.

2 of its 3 bordering counties with figures ran higher, led by Lake County at 76.0%; Beadle County reported 59.3%. Statewide for the same period, Lake County reported the highest share (76.0%) and Davison County the lowest (48.8%).

CDC's ten-year totals for Kingsbury County went from 29 tests (2005 to 2014) to 44 (2008 to 2017), the share going from 75.9% to 68.2%.

Nationally, every county with a figure for the same period pools to 35.7%; Kingsbury County sits 32.5 points above it.

Kingsbury County against South Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Kingsbury County
Kingsbury County4468.2%7.4 pCi/LThis county
South Dakota, pooled62 counties, pooled6,27558.5%Not pooled−9.7 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−32.5 points
Bon Homme Countyhighest in the state6274.2%7.2 pCi/L+6.0 points
Davison Countylowest in the state8448.8%3.8 pCi/L−19.4 points
Clark County, SDborders it977.8%5.9 pCi/L+9.6 points
Hamlin County, SDborders it1376.9%6.3 pCi/L+8.7 points
Lake County, SDborders it5076.0%8.5 pCi/L+7.8 points
Sanborn County, SDborders it771.4%5.5 pCi/L+3.2 points
Brookings County, SDborders it35668.5%6.6 pCi/L+0.3 points
Beadle County, SDborders it5459.3%4.8 pCi/L−8.9 points
Miner County, SDborders it450.0%3.9 pCi/L−18.2 points
Where Kingsbury County's reported results fell, 2008 to 2017, laboratory, beside South Dakota and the United States
ResultKingsbury County testsKingsbury County shareSouth Dakota shareU.S. shareAgainst South Dakota
Under 2 pCi/L818.2%23.6%39.6%−5.4 points
2 to 4 pCi/L613.6%17.9%24.7%−4.3 points
4 pCi/L and above3068.2%58.5%35.7%+9.7 points
Kingsbury County ranked among the 23 South 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
Bon Homme County2 of 236274.2%7.2 pCi/L
Yankton County3 of 2311872.9%6.3 pCi/L
Brown County4 of 236271.0%5.9 pCi/L
Hughes County5 of 237170.4%5.7 pCi/L
Brookings County6 of 2335668.5%6.6 pCi/L
Kingsbury County7 of 234468.2%7.4 pCi/L
Brule County8 of 233767.6%6.4 pCi/L
Hutchinson County9 of 233966.7%5.8 pCi/L
Custer County10 of 2310865.7%6.2 pCi/L
Codington County11 of 237764.9%5.8 pCi/L
Beadle County12 of 235459.3%4.8 pCi/L
Kingsbury County ten-year laboratory totals, against South Dakota's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestSouth Dakota, pooledChange from the row before
2008 to 20174468.2%7.4 pCi/L24.7 pCi/L58.5%−0.4 points
2007 to 20163568.6%7.7 pCi/L24.7 pCi/L57.4%−0.2 points
2006 to 20153268.8%8.4 pCi/L24.7 pCi/L58.8%−7.1 points
2005 to 20142975.9%9.5 pCi/L24.7 pCi/L59.6%First on file

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

Kingsbury County, Geology

The ground under Kingsbury County

Predicted

USGS's geologic map puts all of Kingsbury County's mapped land in one class: high radon potential. All of it lies in the area the map calls Missouri Coteau/James River Lowland/Coteau des Prairies, to which USGS gives a radon index of 14, in the high band (12 to 17).

USGS's geologic areas under Kingsbury County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Missouri Coteau/James River Lowland/Coteau des PrairiesGlacial drift derived largely from Cretaceous marine shale.High1499.9%

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

Kingsbury County beside the ground around it

Kingsbury County has more high-potential ground than South Dakota as a whole: 100% of its land against 56.7%. Of the 7 counties that border it, none has as large a share of high-potential ground; Beadle County comes nearest at 100%.

Share of land by USGS radon potential: Kingsbury County, the 7 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Kingsbury CountyZone 1NoneNone100%
Miner CountyZone 1NoneNone100%
Hamlin CountyZone 1NoneNone100%
Lake CountyZone 1NoneNone100%
Brookings CountyZone 1NoneNone100%
Clark CountyZone 1NoneNone100%
Sanborn CountyZone 1NoneNone100%
Beadle CountyZone 1NoneNone100%
South Dakota66 counties, pooled by land areaVaries1.0%42.3%56.7%

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

Local help

Kingsbury County, Local resources

Radon testing and mitigation in Kingsbury County

What South Dakota's program says
Phone
1-800-438-3367

What it means

Kingsbury County, Questions

Questions about radon in Kingsbury County

Are radon levels high in Kingsbury County?

Over the 2008 to 2017 laboratory totals, 68.2% of the radon tests reported to CDC for Kingsbury County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 7.4 pCi/L. Of 23 South Dakota counties with 30 or more tests for the same period, 6 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Kingsbury County?

Kingsbury County borders 7 counties: Miner County, Hamlin County, Lake County, Brookings County, Clark County, Sanborn County and Beadle County.

Products

Kingsbury County, Products

Testing a home in Kingsbury County

In Kingsbury County, 68.2% of 44 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 58.5% pooled across South Dakota. In Zone 1 the year-round level in Kingsbury 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

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

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Kingsbury County, Bordering counties

Counties bordering Kingsbury County

Calculated by Radon411

Kingsbury County, Cities and towns

Cities and towns in Kingsbury County

The Census Bureau estimates 5,284 residents in Kingsbury County for July 1, 2025, 84 more than in 2020 (+1.6%). Spread over its land, that is 6.3 people to the square mile. No town dominates: De Smet, the largest, has 1,032 residents, 19.5% of the total. CDC's 44 reported tests for 2008 to 2017 work out to 8.3 per 1,000 residents (2025 estimate), close to South Dakota's 6.7.

From De Smet to Bancroft, CDC publishes no figure by town: each reads Kingsbury County's.

The cities and towns in Kingsbury County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
De Smet1,032−3.2%19.5%
Arlingtonextends beyond Kingsbury County926LevelCounted whole
Lake Preston605+3.1%11.4%
Iroquoisextends beyond Kingsbury County294−1.3%Counted whole
Badger137+5.4%2.6%
Oldham121−0.8%2.3%
Erwin41+5.1%0.8%
Hetland20Level0.4%
Bancroft13+8.3%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). A place that extends beyond Kingsbury County is counted whole, so it has no share.

Kingsbury County, Homes

Homes in Kingsbury County

Kingsbury County is a place of houses on their own lots: 84% of its 2,647 homes are detached single-family houses, against 67% across South Dakota. The homes are older than South Dakota's as a whole: half were built before 1967 (1979 for South Dakota), and 44% date from before 1960. Owners live in 81% of the occupied homes (South Dakota: 69%), so for most households a test and a fix are their own to order.

Homes in Kingsbury County, South Dakota, 2019 to 2023
HomesKingsbury CountySouth Dakota
Housing units2,647402,364
Detached houses84%67%
In buildings of 5 or more5%16%
Mobile homes8%8%
Built before 196044%29%
Built since 200020%28%
Middle year built19671979
Owner-occupied81%69%

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