Skip to content
RADON411

Locations and reports

Radon Levels in Minnehaha County, South Dakota

EPA puts Minnehaha County in Zone 1, its highest radon zone, and high results are common there: 58.5% of the 1,920 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

    58.5%

    0.0 pts above SD

    Minnehaha
    58.5%
    SD
    58.5%

    1,920 tests, 2008 to 2017

  • Median result

    4.8pCi/L

    Action level reached

    Minnehaha
    4.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    1,920

    Most tested in SD

    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

    14 of 23

    Middle half

    Minnehaha
    58.5%
    Lake
    76.0%

    By share, of 23 with 30+ tests

Read a result for Minnehaha County

Starts at Minnehaha County's median, 4.8 pCi/L

4.8pCi/L

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

EPA’s reading of 4.8 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. Minnehaha County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Minnehaha County, At a glance

Minnehaha County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Minnehaha County, 2008 to 2017, laboratory
Under 2 pCi/L: 24%2 to 4 pCi/L: 18%4 pCi/L and above: 58%

Of 1,920 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Minnehaha County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L45823.9%
2 to 4 pCi/L33917.7%
4 pCi/L and above1,12358.5%
What these figures count

These are the 1,920 tests reported to CDC for Minnehaha 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

Minnehaha County, Compared

Minnehaha County radon figures, compared

Calculated by Radon411

More than half: 58.5% of the 1,920 radon tests reported to CDC for Minnehaha County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 14th of 23 South Dakota counties with 30 or more tests for the same period. Pooled across 62 South Dakota counties, the share is the same 58.5%.

The median result, 4.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 204.9 pCi/L. The rest split 23.9% under 2 pCi/L and 17.7% 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 58.5% share point the same way here.

5 of its 7 bordering counties with figures ran higher, led by Rock County, MN at 83.8%; McCook County reported 50.0%. 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 Minnehaha County went from 1,276 tests (2005 to 2014) to 1,920 (2008 to 2017), the share going from 61.3% to 58.5%.

Nationally, every county with a figure for the same period pools to 35.7%; Minnehaha County sits 22.8 points above it. CDC also counts 34 tests taken after mitigation in Minnehaha County for the same period: tests in homes where a fix was already in.

Minnehaha County against South Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Minnehaha County
Minnehaha County1,92058.5%4.8 pCi/LThis county
South Dakota, pooled62 counties, pooled6,27558.5%Not pooledLevel
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−22.8 points
Bon Homme Countyhighest in the state6274.2%7.2 pCi/L+15.7 points
Davison Countylowest in the state8448.8%3.8 pCi/L−9.7 points
Rock County, MNborders it21083.8%7.7 pCi/L+25.3 points
Lyon County, IAborders it23777.6%8.3 pCi/L+19.1 points
Lake County, SDborders it5076.0%8.5 pCi/L+17.5 points
Pipestone County, MNborders it36071.4%5.8 pCi/L+12.9 points
Moody County, SDborders it2070.0%6.2 pCi/L+11.5 points
Turner County, SDborders it5858.6%4.8 pCi/L+0.1 points
Lincoln County, SDborders it79556.5%4.7 pCi/L−2.0 points
McCook County, SDborders it3050.0%3.9 pCi/L−8.5 points
Where Minnehaha County's reported results fell, 2008 to 2017, laboratory, beside South Dakota and the United States
ResultMinnehaha County testsMinnehaha County shareSouth Dakota shareU.S. shareAgainst South Dakota
Under 2 pCi/L45823.9%23.6%39.6%+0.3 points
2 to 4 pCi/L33917.7%17.9%24.7%−0.2 points
4 pCi/L and above1,12358.5%58.5%35.7%Level
Minnehaha 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
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
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
Minnehaha 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 20171,92058.5%4.8 pCi/L204.9 pCi/L58.5%+0.1 points
2007 to 20161,66958.4%4.8 pCi/L204.9 pCi/L57.4%−1.1 points
2006 to 20151,52259.5%5.0 pCi/L204.9 pCi/L58.8%−1.8 points
2005 to 20141,27661.3%5.2 pCi/L204.9 pCi/L59.6%First on file

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

Minnehaha County, Geology

The ground under Minnehaha County

Predicted

USGS's geologic map puts all of Minnehaha County's mapped land in one class: high radon potential. The map puts 73.2% of Minnehaha County in the area it calls Loess-Covered Drift Plains and 26.7% in Missouri Coteau/James River Lowland/Coteau des Prairies. 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 Minnehaha County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High1373.2%
Missouri Coteau/James River Lowland/Coteau des PrairiesGlacial drift derived largely from Cretaceous marine shale.High1426.7%

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

Minnehaha County beside the ground around it

Minnehaha County has more high-potential ground than South Dakota as a whole: 99.9% of its land against 56.7%. Of the 8 counties that border it, 7 have more high-potential ground, Lincoln County the most at 100%.

Share of land by USGS radon potential: Minnehaha County, the 8 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Minnehaha CountyZone 1NoneNone99.9%
Moody CountyZone 1NoneNone99.9%
Rock County, MNZone 1NoneNone100%
Lincoln CountyZone 1NoneNone100%
McCook CountyZone 1NoneNone100%
Lake CountyZone 1NoneNone100%
Turner CountyZone 1NoneNone100%
Pipestone County, MNZone 1NoneNone100%
Lyon County, IAZone 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

Minnehaha County, Local resources

Radon testing and mitigation in Minnehaha County

Listed radon businesses with an address in Minnehaha County:

Listed radon professionals by town: Sioux Falls, Garretson

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

What it means

Minnehaha County, Questions

Questions about radon in Minnehaha County

Are radon levels high in Minnehaha County?

Over the 2008 to 2017 laboratory totals, 58.5% of the radon tests reported to CDC for Minnehaha County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.8 pCi/L. Of 23 South Dakota counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Minnehaha County?

Minnehaha County borders 8 counties: Moody County, SD, Rock County, MN, Lincoln County, SD, McCook County, SD, Lake County, SD, Turner County, SD, Pipestone County, MN and Lyon County, IA.

Products

Minnehaha County, Products

Testing a home in Minnehaha County

In Minnehaha County, 58.5% of 1,920 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 Minnehaha 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

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

Explore

Minnehaha County, Bordering counties

Counties bordering Minnehaha County

Calculated by Radon411

Minnehaha County, Cities and towns

Cities and towns in Minnehaha County

Minnehaha County is growing: the Census Bureau puts it at 212,691 residents on July 1, 2025, up 7.6% from 197,688 in 2020. That works out to 264 people per square mile of land. Sioux Falls, the largest place on its list (213,748 residents in all), extends beyond Minnehaha County, so no share of the total is worked out for it. CDC's 1,920 reported tests for 2008 to 2017 work out to 9.0 per 1,000 residents (2025 estimate), close to South Dakota's 6.7.

From Sioux Falls to Sherman, CDC publishes no figure by town: each reads Minnehaha County's.

The cities and towns in Minnehaha County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Sioux Fallsextends beyond Minnehaha County213,748+10.5%Counted whole
Brandon11,306+2.4%5.3%
Dell Rapids3,852−3.2%1.8%
Hartford3,635+8.3%1.7%
Crooks1,415+3.8%0.7%
Baltic1,344+8.0%0.6%
Garretson1,174−3.8%0.6%
Valley Springs889+1.1%0.4%
Colton687−6.7%0.3%
Humboldt569−1.6%0.3%
Sherman77−1.3%Under 0.1%

11 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 Minnehaha County is counted whole, so it has no share.

Minnehaha County, Homes

Homes in Minnehaha County

Of Minnehaha County's 87,043 homes, 60% are detached houses, against 67% across South Dakota; 26% are in buildings of five or more homes. Half of its homes were built before 1986, close to South Dakota's 1979: 23% date from before 1960 and 32% from 2000 or later. 64% 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 Minnehaha County, South Dakota, 2019 to 2023
HomesMinnehaha CountySouth Dakota
Housing units87,043402,364
Detached houses60%67%
In buildings of 5 or more26%16%
Mobile homes4%8%
Built before 196023%29%
Built since 200032%28%
Middle year built19861979
Owner-occupied64%69%

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