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Radon Levels in Lawrence County, South Dakota

EPA puts Lawrence County in Zone 2, its middle radon zone, and high results are common there: 56.9% of the 160 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

    56.9%

    1.6 pts below SD

    Lawrence
    56.9%
    SD
    58.5%

    160 tests, 2008 to 2017

  • Median result

    5.3pCi/L

    Action level reached

    Lawrence
    5.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    160

    7th of 23 by tests

    Lawrence
    160
    Minnehaha
    1,920

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in SD

    15 of 23

    Middle half

    Lawrence
    56.9%
    Lake
    76.0%

    By share, of 23 with 30+ tests

Read a result for Lawrence County

Starts at Lawrence County's median, 5.3 pCi/L

5.3pCi/L

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

EPA’s reading of 5.3 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. Lawrence County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Lawrence County, At a glance

Lawrence County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Lawrence County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 90% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Lawrence County, 2008 to 2017, laboratory

Reported results by concentration band, Lawrence County, 2008 to 2017, laboratory
Under 2 pCi/L: 20%2 to 4 pCi/L: 23%4 pCi/L and above: 57%

Of 160 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Lawrence County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L3220.0%
2 to 4 pCi/L3723.1%
4 pCi/L and above9156.9%
What these figures count

These are the 160 tests reported to CDC for Lawrence 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

Lawrence County, Compared

Lawrence County radon figures, compared

Calculated by Radon411

More than half: 56.9% of the 160 radon tests reported to CDC for Lawrence County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 15th of 23 South Dakota counties with 30 or more tests for the same period. That is 1.6 points below the 58.5% pooled from 62 South Dakota counties.

The median result, 5.3 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 1431.3 pCi/L. The rest split 20.0% under 2 pCi/L and 23.1% from 2 to 4 (South Dakota: 23.6% and 17.9%). The reported tests do not follow EPA's Zone 2 label for Lawrence County (predicted average between 2 and 4 pCi/L): 56.9% of them reached 4 pCi/L, fewer than that label suggests.

2 of its 4 bordering counties with figures ran higher, led by Weston County, WY at 65.6%; Meade 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 Lawrence County went from 103 tests (2005 to 2014) to 160 (2008 to 2017), the share going from 61.2% to 56.9%.

Nationally, every county with a figure for the same period pools to 35.7%; Lawrence County sits 21.2 points above it.

Lawrence County against South Dakota, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Lawrence County
Lawrence County16056.9%5.3 pCi/LThis county
South Dakota, pooled62 counties, pooled6,27558.5%Not pooled+1.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−21.2 points
Lake Countyhighest in the state5076.0%8.5 pCi/L+19.1 points
Davison Countylowest in the state8448.8%3.8 pCi/L−8.1 points
Weston County, WYborders it3265.6%6.3 pCi/L+8.7 points
Crook County, WYborders it5158.8%5.1 pCi/L+1.9 points
Butte County, SDborders it2458.3%5.4 pCi/L+1.4 points
Pennington County, SDborders it1,02953.6%4.3 pCi/L−3.3 points
Meade County, SDborders it19751.8%4.1 pCi/L−5.1 points
Where Lawrence County's reported results fell, 2008 to 2017, laboratory, beside South Dakota and the United States
ResultLawrence County testsLawrence County shareSouth Dakota shareU.S. shareAgainst South Dakota
Under 2 pCi/L3220.0%23.6%39.6%−3.6 points
2 to 4 pCi/L3723.1%17.9%24.7%+5.2 points
4 pCi/L and above9156.9%58.5%35.7%−1.6 points
Lawrence 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
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
Meade County20 of 2319751.8%4.1 pCi/L
Lawrence 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 201716056.9%5.3 pCi/L1431.3 pCi/L58.5%+1.0 points
2007 to 201614355.9%4.9 pCi/L1431.3 pCi/L57.4%−4.6 points
2006 to 201512460.5%5.3 pCi/L1431.3 pCi/L58.8%−0.7 points
2005 to 201410361.2%5.1 pCi/L1431.3 pCi/L59.6%First on file

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

Lawrence County, Geology

The ground under Lawrence County

Predicted

Most of the ground under Lawrence County is one class on USGS's geologic map: 89.5% of its land is moderate radon potential, with 10.5% high. The map puts 89.5% of Lawrence County in the area it calls Black Hills and 10.5% in Black Hills. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 14, in the high band (12 to 17).

USGS's geologic areas under Lawrence County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Black HillsLate Paleozoic sedimentary or Precambrian intrusive igneous rocks.Moderate1189.5%
Black HillsSandstones and shales of Cretaceous age that surround the Black Hills.High1410.5%

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

Lawrence County beside the ground around it

South Dakota as a whole has more high-potential ground than Lawrence County: 56.7% of its land, against 10.5% here. Of the 5 counties that border it, 3 have more high-potential ground, Crook County, WY the most at 45.4%.

Share of land by USGS radon potential: Lawrence County, the 5 counties bordering it and South Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
Lawrence CountyZone 2None89.5%10.5%
Butte CountyZone 2None82.2%17.8%
Crook County, WYZone 1None54.7%45.4%
Pennington CountyZone 2None96.0%4.0%
Meade CountyZone 2None91.1%8.9%
Weston County, WYZone 2None54.9%45.1%
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

Lawrence County, Local resources

Radon testing and mitigation in Lawrence County

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

What it means

Lawrence County, Questions

Questions about radon in Lawrence County

Are radon levels high in Lawrence County?

Over the 2008 to 2017 laboratory totals, 56.9% of the radon tests reported to CDC for Lawrence County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.3 pCi/L. Of 23 South Dakota counties with 30 or more tests for the same period, 14 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Lawrence County?

Lawrence County borders 5 counties: Butte County, SD, Crook County, WY, Pennington County, SD, Meade County, SD and Weston County, WY.

Products

Lawrence County, Products

Testing a home in Lawrence County

In Lawrence County, 56.9% of 160 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 58.5% pooled across South Dakota. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Lawrence County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Lawrence County homes, compared

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Lawrence County, Bordering counties

Counties bordering Lawrence County

Calculated by Radon411

Lawrence County, Cities and towns

Cities and towns in Lawrence County

Lawrence County is growing: the Census Bureau puts it at 29,459 residents on July 1, 2025, up 14.0% from 25,847 in 2020. That works out to 37 people per square mile of land. Its largest town, Spearfish, has 14,154 residents, 48.0% of the total. Together its 5 incorporated places hold 66.8% of those residents; the other 33.2% live outside any of them. CDC's 160 reported tests for 2008 to 2017 work out to 5.4 per 1,000 residents (2025 estimate), close to South Dakota's 6.7.

From Spearfish to Central City, CDC publishes no figure by town: each reads Lawrence County's.

The cities and towns in Lawrence County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Spearfish14,154+15.6%48.0%
Lead3,064+2.9%10.4%
Deadwood1,360+18.4%4.6%
Whitewood981+9.4%3.3%
Central City112+10.9%0.4%

5 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).

Lawrence County, Homes

Homes in Lawrence County

Of Lawrence County's 14,545 homes, 62% are detached houses, against 67% across South Dakota; 14% are in buildings of five or more homes. Half of its homes were built before 1984, close to South Dakota's 1979: 28% 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 Lawrence County, South Dakota, 2019 to 2023
HomesLawrence CountySouth Dakota
Housing units14,545402,364
Detached houses62%67%
In buildings of 5 or more14%16%
Mobile homes11%8%
Built before 196028%29%
Built since 200032%28%
Middle year built19841979
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.