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Radon Levels in Hanson County, South Dakota

EPA puts Hanson County in Zone 1, its highest radon zone, and only 8 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

  • Highest bordering

    47.9%

    Davison County

    Davison
    47.9%

    1 of 5 neighbours have 30+ tests, 2006 to 2015

  • Nearest county

    47.9%

    Davison County, 18 miles

    Davison
    47.9%
    SD
    58.8%

    Share at 4+ pCi/L, 71 tests, 2006 to 2015

  • Ground above low

    100.0%

    1.0 pts above SD

    Hanson
    100.0%
    SD
    99.0%

    Share of land USGS rates moderate or high potential

  • Tests reported

    8

    Too few for a share

    Hanson
    8
    Needed
    30

    2008 to 2017, laboratory

  • 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

Read a result for Hanson County

Starts at EPA's action level

4.0pCi/L

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

EPA’s reading of 4.0 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.

The data

Hanson County, At a glance

Hanson County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

CDC holds 8 reported tests for Hanson County over the 2008 to 2017 laboratory totals, with a median of 2.8 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Hanson County beside the counties around it is how this page reads it.

What these figures count

Only 8 tests were reported to CDC for Hanson County over 2008 to 2017 (laboratory totals), and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor 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

Hanson County, Compared

Hanson County radon figures, compared

Calculated by Radon411

CDC's largest figure for Hanson County rests on 8 tests over the 2008 to 2017 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 12.5 points and no rank or comparison is drawn from it. Results reached as high as 8.0 pCi/L, with a middle value of 2.8 pCi/L.

Davison County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 47.9% of its tests at or above 4 pCi/L. Farther out, Lake County (41 miles away) at 73.7%, Turner County (41 miles away) at 53.3% and Bon Homme County (48 miles away) at 79.5% have figures too. Pooled across 63 South Dakota counties, 58.8% of reported tests reached that level; across every county in the country with a figure, 36.3%.

Statewide for the same period, Bon Homme County reported the highest share (79.5%) and Davison County the lowest (47.9%). EPA's 1993 map puts Hanson County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land high radon potential.

South Dakota, the United States and the counties around Hanson County, 2006 to 2015, laboratory
AreaTestsAt or above 4 pCi/LMedian
South Dakota, pooled63 counties, pooled4,89358.8%Not pooled
United States, pooled2,669 counties, pooled1,805,52836.3%Not pooled
Bon Homme Countyhighest in the state3979.5%8.1 pCi/L
Pennington Countylowest in the state78651.8%4.3 pCi/L
Miner County, SDborders it1080.0%10.0 pCi/L
Hutchinson County, SDborders it2576.0%8.2 pCi/L
Sanborn County, SDborders it366.7%5.8 pCi/L
McCook County, SDborders it1850.0%4.3 pCi/L
Davison County, SDborders it7147.9%3.7 pCi/L
The nearest South Dakota counties to Hanson County with 30 or more tests, 2006 to 2015, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Davison County18 mi7147.9%3.7 pCi/L
Lake County41 mi3873.7%8.3 pCi/L
Turner County41 mi4553.3%4.0 pCi/L
Bon Homme County48 mi3979.5%8.1 pCi/L
Minnehaha County50 mi1,52259.5%5.0 pCi/L
Yankton County50 mi8066.3%5.4 pCi/L
Kingsbury County50 mi3268.8%8.4 pCi/L
Beadle County57 mi4663.0%5.6 pCi/L
Hanson 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 2017825.0%2.8 pCi/L8.0 pCi/L58.5%+5.0 points
2007 to 2016520.0%2.8 pCi/L6.1 pCi/L57.4%Level
2006 to 2015520.0%2.8 pCi/L6.1 pCi/L58.8%−5.0 points
2005 to 2014425.0%2.8 pCi/L6.1 pCi/L59.6%First on file

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

Hanson County, Geology

The ground under Hanson County

Predicted

USGS's geologic map puts all of Hanson 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 Hanson 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.

Hanson County beside the ground around it

Hanson 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; Davison County comes nearest at 100%.

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

What it means

Hanson County, Questions

Questions about radon in Hanson County

Are radon levels high in Hanson County?

Over the 2008 to 2017 laboratory totals, 25.0% of the radon tests reported to CDC for Hanson County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Davison County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 47.9% of its tests at or above 4 pCi/L.

Which counties border Hanson County?

Hanson County borders 5 counties: Davison County, McCook County, Hutchinson County, Miner County and Sanborn County.

Products

Hanson County, Products

Testing a home in Hanson County

No CDC figure names Hanson County; the nearest county with one, Davison County (18 miles away), reported 47.9% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in Hanson 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

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

Explore

Hanson County, Bordering counties

Counties bordering Hanson County

Calculated by Radon411

Hanson County, Cities and towns

Cities and towns in Hanson County

Hanson County's population has barely moved since 2020: 3,456 residents on July 1, 2025 against 3,466 then, by the Census Bureau's estimates. Spread over its land, that is 8.0 people to the square mile. No town dominates: Alexandria, the largest, has 655 residents, 19.0% of the total. Together its 4 incorporated places hold 35.3% of those residents; the other 64.7% live outside any of them. Reported testing is thin here: 8 tests over 2008 to 2017, or 2.3 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 6.7.

From Alexandria to Farmer, CDC publishes no figure by town: each reads Hanson County's.

The cities and towns in Hanson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Alexandria655+0.3%19.0%
Emery465−3.9%13.5%
Fulton85+1.2%2.5%
Farmer16Level0.5%

4 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).

Hanson County, Homes

Homes in Hanson County

Hanson County is a place of houses on their own lots: 92% of its 1,289 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 1958 (1979 for South Dakota), and 52% date from before 1960. Owners live in 89% of the occupied homes (South Dakota: 69%), so for most households a test and a fix are their own to order.

Homes in Hanson County, South Dakota, 2019 to 2023
HomesHanson CountySouth Dakota
Housing units1,289402,364
Detached houses92%67%
In buildings of 5 or more1%16%
Mobile homes4%8%
Built before 196052%29%
Built since 200020%28%
Middle year built19581979
Owner-occupied89%69%

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