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Radon Levels in Buffalo County, South Dakota

EPA puts Buffalo County in Zone 1, its highest radon zone, and only 1 radon test from it is on file with CDC (2006 to 2015, laboratory totals). 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

  • Highest bordering

    62.5%

    Brule County

    Brule
    62.5%

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

  • Nearest county

    62.5%

    Brule County, 25 miles

    Brule
    62.5%
    SD
    58.8%

    Share at 4+ pCi/L, 32 tests, 2006 to 2015

  • Ground above low

    100.0%

    1.0 pts above SD

    Buffalo
    100.0%
    SD
    99.0%

    Share of land USGS rates moderate or high potential

  • Tests reported

    1

    Too few for a share

    Buffalo
    1
    Needed
    30

    2006 to 2015, 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 Buffalo 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.

Interpret this readingWhat a fix costs

The data

Buffalo County, At a glance

Buffalo County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Buffalo 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 Buffalo County, 2006 to 2015, laboratory

CDC holds 1 reported test for Buffalo County over the 2006 to 2015 laboratory totals, a result of 10.9 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Buffalo County beside the counties around it is how this page reads it.

What these figures count

Only 1 test was reported to CDC for Buffalo County over 2006 to 2015 (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: 2006 to 2015, laboratory. Measured data period: 2005 to 2015 (every CDC figure on file).

How to read these figures

Buffalo County, Compared

Buffalo County radon figures, compared

Calculated by Radon411

CDC's largest figure for Buffalo County rests on 1 test over the 2006 to 2015 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 100.0 points and no rank or comparison is drawn from it. Results reached as high as 10.9 pCi/L, with a middle value of 10.9 pCi/L.

Brule County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 62.5% of its tests at or above 4 pCi/L. Farther out, Hughes County (45 miles away) at 66.7%, Beadle County (52 miles away) at 63.0% and Davison County (60 miles away) at 47.9% 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 Buffalo 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 Buffalo 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
Davison Countylowest in the state7147.9%3.7 pCi/L
Lyman County, SDborders it5100.0%20.0 pCi/L
Hyde County, SDborders it580.0%4.9 pCi/L
Hand County, SDborders it1080.0%4.8 pCi/L
Jerauld County, SDborders it2272.7%8.2 pCi/L
Brule County, SDborders it3262.5%6.3 pCi/L
The nearest South Dakota counties to Buffalo County with 30 or more tests, 2006 to 2015, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Brule County25 mi3262.5%6.3 pCi/L
Hughes County45 mi3066.7%5.5 pCi/L
Beadle County52 mi4663.0%5.6 pCi/L
Davison County60 mi7147.9%3.7 pCi/L
Kingsbury County87 mi3268.8%8.4 pCi/L
Edmunds County93 mi6861.8%5.0 pCi/L
Bon Homme County100 mi3979.5%8.1 pCi/L
Lake County103 mi3873.7%8.3 pCi/L
Buffalo County ten-year laboratory totals, against South Dakota's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestSouth Dakota, pooledChange from the row before
2006 to 20151100.0%10.9 pCi/L10.9 pCi/L58.8%Level
2005 to 20141100.0%10.9 pCi/L10.9 pCi/L59.6%First on file

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

Buffalo County, Geology

The ground under Buffalo County

Predicted

USGS's geologic map puts all of Buffalo 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 Buffalo 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.

Buffalo County beside the ground around it

Buffalo 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; Brule County comes nearest at 100%.

Share of land by USGS radon potential: Buffalo County, the 5 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Buffalo CountyZone 1NoneNone100%
Hand CountyZone 1NoneNone100%
Brule CountyZone 1NoneNone100%
Hyde CountyZone 1NoneNone100%
Jerauld CountyZone 1NoneNone100%
Lyman CountyZone 1None44.3%55.7%
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

Buffalo County, Local resources

Radon testing and mitigation in Buffalo County

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

What it means

Buffalo County, Questions

Questions about radon in Buffalo County

Are radon levels high in Buffalo County?

Over the 2006 to 2015 laboratory totals, 100.0% of the radon tests reported to CDC for Buffalo County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 10.9 pCi/L. Brule County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 62.5% of its tests at or above 4 pCi/L.

Which counties border Buffalo County?

Buffalo County borders 5 counties: Hand County, Brule County, Hyde County, Jerauld County and Lyman County.

Products

Buffalo County, Products

Testing a home in Buffalo County

No CDC figure names Buffalo County; the nearest county with one, Brule County (25 miles away), reported 62.5% 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 Buffalo 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

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

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Buffalo County, Bordering counties

Counties bordering Buffalo County

Calculated by Radon411

Buffalo County, Residents

Who lives in Buffalo County

Buffalo County has been losing residents: from 1,933 in 2020 to 1,802 on July 1, 2025, a fall of 6.8% by the Census Bureau's estimates. Spread over its land, that is 3.8 people to the square mile. Reported testing is thin here: 1 test over 2006 to 2015, or 0.6 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 5.2.

Census lists no incorporated place in Buffalo County: every home in it reads the county's figures.

Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Buffalo County, Homes

Homes in Buffalo County

Of Buffalo County's 577 homes, 66% are detached houses, against 67% across South Dakota; 24% are mobile homes. Half of its homes were built before 1976, close to South Dakota's 1979: 12% date from before 1960 and 10% from 2000 or later. 53% 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 Buffalo County, South Dakota, 2019 to 2023
HomesBuffalo CountySouth Dakota
Housing units577402,364
Detached houses66%67%
In buildings of 5 or more7%16%
Mobile homes24%8%
Built before 196012%29%
Built since 200010%28%
Middle year built19761979
Owner-occupied53%69%

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