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Radon Levels in Yankton County, South Dakota

EPA puts Yankton County in Zone 1, its highest radon zone, and high results are common there: 72.9% of the 118 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

    72.9%

    14.4 pts above SD

    Yankton
    72.9%
    SD
    58.5%

    118 tests, 2008 to 2017

  • Median result

    6.3pCi/L

    Action level reached

    Yankton
    6.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    118

    8th of 23 by tests

    Yankton
    118
    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

    3 of 23

    Top quarter

    Yankton
    72.9%
    Lake
    76.0%

    By share, of 23 with 30+ tests

Read a result for Yankton County

Starts at Yankton County's median, 6.3 pCi/L

6.3pCi/L

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

EPA’s reading of 6.3 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. Yankton County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Yankton County, At a glance

Yankton County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Yankton County, 2008 to 2017, laboratory
Under 2 pCi/L: 18%2 to 4 pCi/L: 9%4 pCi/L and above: 73%

Of 118 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Yankton County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2117.8%
2 to 4 pCi/L119.3%
4 pCi/L and above8672.9%
What these figures count

These are the 118 tests reported to CDC for Yankton 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

Yankton County, Compared

Yankton County radon figures, compared

Calculated by Radon411

More than half: 72.9% of the 118 radon tests reported to CDC for Yankton County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 3rd of 23 South Dakota counties with 30 or more tests for the same period. That is 14.4 points above the 58.5% pooled from 62 South Dakota counties.

The median result, 6.3 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 73.4 pCi/L. The rest split 17.8% under 2 pCi/L and 9.3% 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 72.9% share point the same way here.

2 of its 6 bordering counties with figures ran higher, led by Cedar County, NE at 76.8%; Clay County reported 51.8%. 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 Yankton County went from 75 tests (2005 to 2014) to 118 (2008 to 2017), the share going from 68.0% to 72.9%.

Nationally, every county with a figure for the same period pools to 35.7%; Yankton County sits 37.2 points above it.

Yankton County against South Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Yankton County
Yankton County11872.9%6.3 pCi/LThis county
South Dakota, pooled62 counties, pooled6,27558.5%Not pooled−14.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−37.2 points
Lake Countyhighest in the state5076.0%8.5 pCi/L+3.1 points
Davison Countylowest in the state8448.8%3.8 pCi/L−24.1 points
Cedar County, NEborders it48776.8%8.3 pCi/L+3.9 points
Bon Homme County, SDborders it6274.2%7.2 pCi/L+1.3 points
Knox County, NEborders it40168.8%6.2 pCi/L−4.1 points
Hutchinson County, SDborders it3966.7%5.8 pCi/L−6.2 points
Turner County, SDborders it5858.6%4.8 pCi/L−14.3 points
Clay County, SDborders it8351.8%4.2 pCi/L−21.1 points
Where Yankton County's reported results fell, 2008 to 2017, laboratory, beside South Dakota and the United States
ResultYankton County testsYankton County shareSouth Dakota shareU.S. shareAgainst South Dakota
Under 2 pCi/L2117.8%23.6%39.6%−5.8 points
2 to 4 pCi/L119.3%17.9%24.7%−8.6 points
4 pCi/L and above8672.9%58.5%35.7%+14.4 points
Yankton 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
Lake County1 of 235076.0%8.5 pCi/L
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
Yankton 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 201711872.9%6.3 pCi/L73.4 pCi/L58.5%+7.9 points
2007 to 20168065.0%5.3 pCi/L73.4 pCi/L57.4%−1.3 points
2006 to 20158066.3%5.4 pCi/L73.4 pCi/L58.8%−1.7 points
2005 to 20147568.0%5.4 pCi/L73.4 pCi/L59.6%First on file

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

Yankton County, Geology

The ground under Yankton County

Predicted

USGS's geologic map puts all of Yankton County's mapped land in one class: high radon potential. 96.8% 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 Yankton 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.High1496.8%
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High132.0%
Sharon SpringsCretaceous Pierre Shale bedrock, including the uranium-bearing Sharon Springs Member.High121.1%

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

Yankton County beside the ground around it

Yankton County has more high-potential ground than South Dakota as a whole: 100% of its land against 56.7%. Of the 6 counties that border it, none has as large a share of high-potential ground; Bon Homme County comes nearest at 100%.

Share of land by USGS radon potential: Yankton County, the 6 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Yankton CountyZone 1NoneNone100%
Clay CountyZone 1NoneNone100%
Bon Homme CountyZone 1NoneNone100%
Cedar County, NEZone 1NoneNone100%
Turner CountyZone 1NoneNone100%
Hutchinson CountyZone 1NoneNone100%
Knox County, NEZone 1None20.0%80.0%
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

Yankton County, Local resources

Radon testing and mitigation in Yankton County

Listed radon businesses with an address in Yankton County:

Listed radon professionals by town: Yankton

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

What it means

Yankton County, Questions

Questions about radon in Yankton County

Are radon levels high in Yankton County?

Over the 2008 to 2017 laboratory totals, 72.9% of the radon tests reported to CDC for Yankton County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.3 pCi/L. Of 23 South Dakota counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Yankton County?

Yankton County borders 6 counties: Clay County, SD, Bon Homme County, SD, Cedar County, NE, Turner County, SD, Hutchinson County, SD and Knox County, NE.

Products

Yankton County, Products

Testing a home in Yankton County

In Yankton County, 72.9% of 118 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 Yankton 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

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

Explore

Yankton County, Bordering counties

Counties bordering Yankton County

Calculated by Radon411

Yankton County, Cities and towns

Cities and towns in Yankton County

The Census Bureau estimates 23,635 residents in Yankton County for July 1, 2025, 344 more than in 2020 (+1.5%). That works out to 45 people per square mile of land. Yankton alone is home to 15,816 of them, 66.9% of the total. CDC's 118 reported tests for 2008 to 2017 work out to 5.0 per 1,000 residents (2025 estimate), close to South Dakota's 6.7.

From Yankton to Utica, CDC publishes no figure by town: each reads Yankton County's.

The cities and towns in Yankton County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Yankton15,816+2.5%66.9%
Ireneextends beyond Yankton County439+2.6%Counted whole
Gayville375−3.4%1.6%
Mission Hill187−3.1%0.8%
Volin157−0.6%0.7%
Lesterville110Level0.5%
Utica69−2.8%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). A place that extends beyond Yankton County is counted whole, so it has no share.

Yankton County, Homes

Homes in Yankton County

Of Yankton County's 10,497 homes, 71% are detached houses, against 67% across South Dakota; 14% are in buildings of five or more homes. Half of its homes were built before 1976, close to South Dakota's 1979: 30% date from before 1960 and 20% from 2000 or later. 72% of occupied homes are lived in by their owner (South Dakota: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Yankton County, South Dakota, 2019 to 2023
HomesYankton CountySouth Dakota
Housing units10,497402,364
Detached houses71%67%
In buildings of 5 or more14%16%
Mobile homes5%8%
Built before 196030%29%
Built since 200020%28%
Middle year built19761979
Owner-occupied72%69%

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