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Butte County, South Dakota
Shrink-swell clay limits houses without basements on 72% of Butte County's mapped land, a higher share than 97% of US counties and the 5th highest of 66 South Dakota counties. A shallow water table limits basements on 6%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list no flood losses here since 2016. 48% of homes were built before 1980, against 50% nationally; the median home dates from 1982.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Butte County
| Expansive clay (limits slab homes) | 71.5% |
| High water table (limits basements) | 5.7% |
| Septic fields very limited | 86.6% |
| Clay swell (LEP, by area) | 9.8% |
| High-swell land (LEP 6%+) | 74.5% |
| Mapped soil | 1,451,008 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Lismas | 10% | n/a |
| Winler | 10% | n/a |
| Pierre | 6% | n/a |
| Kyle | 5% | n/a |
| Swanboy | 5% | n/a |
| Wasa | 4% | n/a |
How we count · survey areas SD019 (2025-09-10)
What the numbers mean here
Clay swell averages a linear extensibility of 9.8% by land area here, and 75% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 72% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 72% of Butte County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 13.10 in, 3.41 in below the 1991-2020 average year of 16.51 in.
USDA rates 87% of the land very limited for septic absorption fields.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 31 of the last 52 weeks; the most was 100% of its area, in 11 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 29% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Butte County since 2016.
Rain
| Average year, 1991-2020 | 16.51 in |
| 12 months to August 2026 | 13.10 in (-3.41) |
| 2025 | 21.77 in (+5.26) |
| Wettest year since 1895 | 1946: 25.38 in |
| Driest year since 1895 | 1936: 8.12 in |
| Days with 1 inch or more, normal at NEWELL (13 mi away) | 2.6 |
Homes
| Housing units | 4,783 |
| Median year built | 1982 |
| Built before 1980 | 48% |
| Built 2000 or later | 27% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $244,600 |
| Single-family detached | 60% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Lawrence County, SD | 41 mi | 22% | 1% |
| Meade County, SD | 44 mi | 49% | 1% |
| Harding County, SD | 48 mi | 13% | 2% |
| Crook County, WY | 56 mi | 46% | under 1% |
| Perkins County, SD | 65 mi | 18% | 2% |
| Carter County, MT | 65 mi | 52% | 1% |
| Pennington County, SD | 70 mi | 52% | 1% |
| Custer County, SD | 84 mi | 17% | 1% |
Sources: USDA SSURGO (September 10, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status