BasementSoil

South Dakota: basement moisture and foundation risk by county

66 counties, ranked by our combined index. Highest combined risk is Brown County (62), lowest is Custer County (31). The worst soil for foundation cracks specifically is in Harding County.

Where in South Dakota the ground is worse

Every county in the state, coloured by the soil values below. Click a county to open its report; switch what the colour means with the buttons. The pattern is geology, not administration — risk stops at the edge of a physiographic region, not at a county line.

Aurora County, SD — combined 45/100, moisture 53, movement 43, water table 30Beadle County, SD — combined 53/100, moisture 54, movement 42, water table 66Bennett County, SD — combined 52/100, moisture 40, movement 84, water table 30Bon Homme County, SD — combined 60/100, moisture 52, movement 66, water table 66Brookings County, SD — combined 43/100, moisture 50, movement 42, water table 30Brown County, SD — combined 62/100, moisture 54, movement 69, water table 66Brule County, SD — combined 58/100, moisture 54, movement 58, water table 66Buffalo County, SD — combined 48/100, moisture 52, movement 44, water table 46Butte County, SD — combined 33/100, moisture 31, movement 38, water table 30Campbell County, SD — combined 54/100, moisture 39, movement 91, water table 30Charles Mix County, SD — combined 52/100, moisture 53, movement 56, water table 46Clark County, SD — combined 49/100, moisture 53, movement 45, water table 46Clay County, SD — combined 45/100, moisture 52, movement 47, water table 30Codington County, SD — combined 52/100, moisture 51, movement 43, water table 66Corson County, SD — combined 54/100, moisture 41, movement 91, water table 30Custer County, SD — combined 31/100, moisture 29, movement 34, water table 30Davison County, SD — combined 55/100, moisture 52, movement 52, water table 66Day County, SD — combined 54/100, moisture 55, movement 43, water table 66Deuel County, SD — combined 60/100, moisture 54, movement 63, water table 66Dewey County, SD — combined 42/100, moisture 37, movement 59, water table 30Douglas County, SD — combined 56/100, moisture 49, movement 72, water table 46Edmunds County, SD — combined 56/100, moisture 51, movement 57, water table 66Fall River County, SD — combined 52/100, moisture 40, movement 94, water table 16Faulk County, SD — combined 59/100, moisture 53, movement 61, water table 66Grant County, SD — combined 57/100, moisture 54, movement 68, water table 46Gregory County, SD — combined 52/100, moisture 50, movement 70, water table 30Haakon County, SD — combined 51/100, moisture 41, movement 80, water table 30Hamlin County, SD — combined 60/100, moisture 51, movement 67, water table 66Hand County, SD — combined 49/100, moisture 50, movement 49, water table 46Hanson County, SD — combined 48/100, moisture 51, movement 57, water table 30Harding County, SD — combined 58/100, moisture 42, movement 100, water table 30Hughes County, SD — combined 46/100, moisture 42, movement 63, water table 30Hutchinson County, SD — combined 44/100, moisture 52, movement 44, water table 30Hyde County, SD — combined 56/100, moisture 40, movement 96, water table 30Jackson County, SD — combined 43/100, moisture 39, movement 67, water table 16Jerauld County, SD — combined 44/100, moisture 53, movement 41, water table 30Jones County, SD — combined 47/100, moisture 42, movement 66, water table 30Kingsbury County, SD — combined 50/100, moisture 52, movement 50, water table 46Lake County, SD — combined 53/100, moisture 51, movement 48, water table 66Lawrence County, SD — combined 31/100, moisture 29, movement 34, water table 30Lincoln County, SD — combined 56/100, moisture 53, movement 52, water table 66Lyman County, SD — combined 55/100, moisture 41, movement 93, water table 30Marshall County, SD — combined 49/100, moisture 52, movement 46, water table 46McCook County, SD — combined 49/100, moisture 55, movement 53, water table 30McPherson County, SD — combined 52/100, moisture 50, movement 60, water table 46Meade County, SD — combined 53/100, moisture 39, movement 89, water table 30Mellette County, SD — combined 44/100, moisture 37, movement 65, water table 30Miner County, SD — combined 49/100, moisture 51, movement 48, water table 46Minnehaha County, SD — combined 56/100, moisture 50, movement 71, water table 46Moody County, SD — combined 47/100, moisture 51, movement 43, water table 46Pennington County, SD — combined 47/100, moisture 39, movement 80, water table 16Perkins County, SD — combined 46/100, moisture 39, movement 68, water table 30Potter County, SD — combined 52/100, moisture 41, movement 84, water table 30Roberts County, SD — combined 50/100, moisture 52, movement 62, water table 30Sanborn County, SD — combined 53/100, moisture 50, movement 61, water table 46Spink County, SD — combined 51/100, moisture 50, movement 66, water table 30Stanley County, SD — combined 57/100, moisture 41, movement 100, water table 30Sully County, SD — combined 53/100, moisture 41, movement 87, water table 30Todd County, SD — combined 46/100, moisture 39, movement 68, water table 30Tripp County, SD — combined 57/100, moisture 41, movement 98, water table 30Turner County, SD — combined 52/100, moisture 50, movement 59, water table 46Union County, SD — combined 52/100, moisture 55, movement 52, water table 46Walworth County, SD — combined 55/100, moisture 41, movement 93, water table 30Yankton County, SD — combined 53/100, moisture 50, movement 47, water table 66Ziebach County, SD — combined 44/100, moisture 39, movement 61, water table 30
  • Low (0–27)
  • Moderate (28–49)
  • Elevated (50–74)
  • High (75–100)

County boundaries: US Census TIGER (public domain), simplified for display. Colours are our index from USDA SSURGO fields where loaded, otherwise from our regional model — each county page states which. How the index is calculated.

CountyIndexMoistureCracksWater tableRegion
Brown County62546966Dakota prairie till plain
Bon Homme County60526666Dakota prairie till plain
Deuel County60546366Dakota prairie till plain
Hamlin County60516766Dakota prairie till plain
Faulk County59536166Dakota prairie till plain
Brule County58545866Dakota prairie till plain
Harding County584210030Missouri Plateau (unglaciated Great Plains)
Grant County57546846Dakota prairie till plain
Stanley County574110030Missouri Plateau (unglaciated Great Plains)
Tripp County57419830Missouri Plateau (unglaciated Great Plains)
Douglas County56497246Dakota prairie till plain
Edmunds County56515766Dakota prairie till plain
Hyde County56409630Missouri Plateau (unglaciated Great Plains)
Lincoln County56535266Dakota prairie till plain
Minnehaha County56507146Dakota prairie till plain
Davison County55525266Dakota prairie till plain
Lyman County55419330Missouri Plateau (unglaciated Great Plains)
Walworth County55419330Missouri Plateau (unglaciated Great Plains)
Campbell County54399130Missouri Plateau (unglaciated Great Plains)
Corson County54419130Missouri Plateau (unglaciated Great Plains)
Day County54554366Dakota prairie till plain
Beadle County53544266Dakota prairie till plain
Lake County53514866Dakota prairie till plain
Meade County53398930Missouri Plateau (unglaciated Great Plains)
Sanborn County53506146Dakota prairie till plain
Sully County53418730Missouri Plateau (unglaciated Great Plains)
Yankton County53504766Dakota prairie till plain
Bennett County52408430Missouri Plateau (unglaciated Great Plains)
Charles Mix County52535646Dakota prairie till plain
Codington County52514366Dakota prairie till plain
Fall River County52409416Missouri Plateau (unglaciated Great Plains)
Gregory County52507030Dakota prairie till plain
McPherson County52506046Dakota prairie till plain
Potter County52418430Missouri Plateau (unglaciated Great Plains)
Turner County52505946Dakota prairie till plain
Union County52555246Dakota prairie till plain
Haakon County51418030Missouri Plateau (unglaciated Great Plains)
Spink County51506630Dakota prairie till plain
Kingsbury County50525046Dakota prairie till plain
Roberts County50526230Dakota prairie till plain
Clark County49534546Dakota prairie till plain
Hand County49504946Dakota prairie till plain
Marshall County49524646Dakota prairie till plain
McCook County49555330Dakota prairie till plain
Miner County49514846Dakota prairie till plain
Buffalo County48524446Dakota prairie till plain
Hanson County48515730Dakota prairie till plain
Jones County47426630Missouri Plateau (unglaciated Great Plains)
Moody County47514346Dakota prairie till plain
Pennington County47398016Missouri Plateau (unglaciated Great Plains)
Hughes County46426330Missouri Plateau (unglaciated Great Plains)
Oglala Lakota County46388016Missouri Plateau (unglaciated Great Plains)
Perkins County46396830Missouri Plateau (unglaciated Great Plains)
Todd County46396830Missouri Plateau (unglaciated Great Plains)
Aurora County45534330Dakota prairie till plain
Clay County45524730Dakota prairie till plain
Hutchinson County44524430Dakota prairie till plain
Jerauld County44534130Dakota prairie till plain
Mellette County44376530Missouri Plateau (unglaciated Great Plains)
Ziebach County44396130Missouri Plateau (unglaciated Great Plains)
Brookings County43504230Dakota prairie till plain
Jackson County43396716Missouri Plateau (unglaciated Great Plains)
Dewey County42375930Missouri Plateau (unglaciated Great Plains)
Butte County33313830Rocky Mountains
Custer County31293430Rocky Mountains
Lawrence County31293430Rocky Mountains

Values from USDA NRCS SSURGO where available, otherwise our regional model — each county page states which. Methodology.

The physiographic regions inside South Dakota

State lines are political; soil follows geology. These are the distinct ground types inside South Dakota and why each behaves the way it does.

Dakota prairie till plain

The dry climate hides the mechanism: the profile shrinks through dry years, swells after a wet one, and the footing moves. A cycle, not permanent damp.

39 counties: Aurora County, Beadle County, Bon Homme County, Brookings County, Brown County, Brule County, Buffalo County, Charles Mix County, Clark County, Clay County, Codington County, Davison County, Day County, Deuel County, Douglas County, Edmunds County, Faulk County, Grant County, Gregory County, Hamlin County, Hand County, Hanson County, Hutchinson County, Jerauld County, Kingsbury County, Lake County, Lincoln County, Marshall County, McCook County, McPherson County, Miner County, Minnehaha County, Moody County, Roberts County, Sanborn County, Spink County, Turner County, Union County, Yankton County

Missouri Plateau (unglaciated Great Plains)

The water table is deep, so basements rarely flood — but Pierre Shale is one of the most expansive substrates in North America. The risk here is mechanical, not hydraulic.

24 counties: Bennett County, Campbell County, Corson County, Dewey County, Fall River County, Haakon County, Harding County, Hughes County, Hyde County, Jackson County, Jones County, Lyman County, Meade County, Mellette County, Oglala Lakota County, Pennington County, Perkins County, Potter County, Stanley County, Sully County, Todd County, Tripp County, Walworth County, Ziebach County

Rocky Mountains

Shallow bedrock and coarse material. Basements are shallow or absent, and the problem is spring meltwater rather than a water table.

3 counties: Butte County, Custer County, Lawrence County

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