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Radon Levels in Davison County, South Dakota

EPA puts Davison County in Zone 1, its highest radon zone, and high results are common there: 48.8% of the 84 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

    48.8%

    9.7 pts below SD

    Davison
    48.8%
    SD
    58.5%

    84 tests, 2008 to 2017

  • Median result

    3.8pCi/L

    Below action level

    Davison
    3.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    84

    10th of 23 by tests

    Davison
    84
    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

    23 of 23

    Lowest quarter

    Davison
    48.8%
    Lake
    76.0%

    By share, of 23 with 30+ tests

Read a result for Davison County

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

Interpret this readingWhat a fix costs

The data

Davison County, At a glance

Davison County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Davison County, 2008 to 2017, laboratory
Under 2 pCi/L: 27%2 to 4 pCi/L: 24%4 pCi/L and above: 49%

Of 84 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Davison County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2327.4%
2 to 4 pCi/L2023.8%
4 pCi/L and above4148.8%
What these figures count

These are the 84 tests reported to CDC for Davison 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

Davison County, Compared

Davison County radon figures, compared

Calculated by Radon411

In Davison County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (41 of 84) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 13.1 points higher. Across 62 South Dakota counties pooled together, 58.5% of tests reached that level, so Davison County runs 9.7 points below its state.

Hutchinson County, the one bordering county with a figure for the same period, reported 66.7%. By share, Davison County is 23rd of 23 South 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 22.9 pCi/L. Below the action level, 23 tests (27.4%) came in under 2 pCi/L, against 23.6% statewide, and 20 tests (23.8%) fell between 2 and 4, against 17.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 48.8% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

CDC's ten-year totals for Davison County went from 64 tests (2005 to 2014) to 84 (2008 to 2017), the share going from 46.9% to 48.8%.

Davison County against South Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Davison County
Davison County8448.8%3.8 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−13.1 points
Lake Countyhighest in the state5076.0%8.5 pCi/L+27.2 points
McCook Countylowest in the state3050.0%3.9 pCi/L+1.2 points
Sanborn County, SDborders it771.4%5.5 pCi/L+22.6 points
Hutchinson County, SDborders it3966.7%5.8 pCi/L+17.9 points
Aurora County, SDborders it1540.0%2.7 pCi/L−8.8 points
Hanson County, SDborders it825.0%2.8 pCi/L−23.8 points
Douglas County, SDborders it30.0%1.3 pCi/L−48.8 points
Where Davison County's reported results fell, 2008 to 2017, laboratory, beside South Dakota and the United States
ResultDavison County testsDavison County shareSouth Dakota shareU.S. shareAgainst South Dakota
Under 2 pCi/L2327.4%23.6%39.6%+3.8 points
2 to 4 pCi/L2023.8%17.9%24.7%+5.9 points
4 pCi/L and above4148.8%58.5%35.7%−9.7 points
Davison 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
Turner County13 of 235858.6%4.8 pCi/L
Minnehaha County14 of 231,92058.5%4.8 pCi/L
Lawrence County15 of 2316056.9%5.3 pCi/L
Lincoln County16 of 2379556.5%4.7 pCi/L
Grant County17 of 237855.1%5.0 pCi/L
Pennington County18 of 231,02953.6%4.3 pCi/L
Clay County19 of 238351.8%4.2 pCi/L
Meade County20 of 2319751.8%4.1 pCi/L
Union County21 of 2334851.1%4.1 pCi/L
McCook County22 of 233050.0%3.9 pCi/L
Davison County23 of 238448.8%3.8 pCi/L
Davison 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 20178448.8%3.8 pCi/L22.9 pCi/L58.5%+1.7 points
2007 to 20166847.1%3.7 pCi/L22.9 pCi/L57.4%−0.8 points
2006 to 20157147.9%3.7 pCi/L22.9 pCi/L58.8%+1.0 points
2005 to 20146446.9%3.7 pCi/L22.9 pCi/L59.6%First on file

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

Davison County, Geology

The ground under Davison County

Predicted

USGS's geologic map puts all of Davison 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 Davison 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.High14100%

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

Davison County beside the ground around it

Davison County has more high-potential ground than South Dakota as a whole: 100% of its land against 56.7%. Of the 5 counties that border it, none has as large a share of high-potential ground; Aurora County comes nearest at 100%.

Share of land by USGS radon potential: Davison County, the 5 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Davison CountyZone 1NoneNone100%
Hanson CountyZone 1NoneNone100%
Aurora CountyZone 1NoneNone100%
Sanborn CountyZone 1NoneNone100%
Douglas CountyZone 1NoneNone100%
Hutchinson 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

Davison County, Local resources

Radon testing and mitigation in Davison County

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

What it means

Davison County, Questions

Questions about radon in Davison County

Are radon levels high in Davison County?

Over the 2008 to 2017 laboratory totals, 48.8% of the radon tests reported to CDC for Davison County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.8 pCi/L. Of 23 South Dakota counties with 30 or more tests for the same period, 22 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Davison County?

Davison County borders 5 counties: Hanson County, Aurora County, Sanborn County, Douglas County and Hutchinson County.

Products

Davison County, Products

Testing a home in Davison County

In Davison County, 48.8% of 84 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 Davison 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

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

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Davison County, Bordering counties

Counties bordering Davison County

Calculated by Radon411

Davison County, Cities and towns

Cities and towns in Davison County

The Census Bureau estimates 20,069 residents in Davison County for July 1, 2025, 109 more than in 2020 (+0.5%). That works out to 46 people per square mile of land. Mitchell alone is home to 15,756 of them, 78.5% of the total. Together its 3 incorporated places hold 82.6% of those residents; the other 17.4% live outside any of them. Reported testing is thin here: 84 tests over 2008 to 2017, or 4.2 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 6.7.

From Mitchell to Ethan, CDC publishes no figure by town: each reads Davison County's.

The cities and towns in Davison County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Mitchell15,756+0.5%78.5%
Mount Vernon462+0.9%2.3%
Ethan363+1.1%1.8%

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).

Davison County, Homes

Homes in Davison County

Of Davison County's 9,550 homes, 64% are detached houses, against 67% across South Dakota; 20% are in buildings of five or more homes. The homes are older than South Dakota's as a whole: half were built before 1971 (1979 for South Dakota), and 37% date from before 1960. 63% 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 Davison County, South Dakota, 2019 to 2023
HomesDavison CountySouth Dakota
Housing units9,550402,364
Detached houses64%67%
In buildings of 5 or more20%16%
Mobile homes6%8%
Built before 196037%29%
Built since 200018%28%
Middle year built19711979
Owner-occupied63%69%

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