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McPherson County, South Dakota
A shallow water table limits basements on 22% of McPherson County's mapped land. Shrink-swell clay limits houses without basements on 18%.
None 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. 78% of homes were built before 1980, against 50% nationally; the median home dates from 1962.
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 McPherson County
| Expansive clay (limits slab homes) | 17.5% |
| High water table (limits basements) | 21.9% |
| Septic fields very limited | 46.1% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 21.8% |
| Mapped soil | 737,421 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Williams | 24% | 0% |
| Bowbells | 11% | n/a |
| Zahl | 9% | n/a |
| Lehr | 5% | n/a |
| Parnell | 4% | n/a |
| Noonan | 4% | n/a |
How we count · survey areas SD089 (2025-09-10)
What the numbers mean here
Clay swell averages a linear extensibility of 4.5% by land area here, and 22% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 18% of the mapped land.
On 22% of McPherson County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 17.97 in, 3.05 in below the 1991-2020 average year of 21.02 in.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 6 of the last 52 weeks; the most was 32.4% of its area, in 6 weeks, most recently on the September 29, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 84.7% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in McPherson County since 2016.
Rain
| Average year, 1991-2020 | 21.02 in |
| 12 months to August 2026 | 17.97 in (-3.05) |
| 2025 | 21.70 in (+0.68) |
| Wettest year since 1895 | 1993: 28.16 in |
| Driest year since 1895 | 1936: 6.97 in |
| Days with 1 inch or more, normal at ASHLEY (16 mi away) | 3.6 |
Homes
| Housing units | 1,205 |
| Median year built | 1962 |
| Built before 1980 | 78% |
| Built 2000 or later | 9% |
| Owner-occupied | 81% |
| Median value, owner-occupied | $85,600 |
| Single-family detached | 85% |
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 |
|---|---|---|---|
| McIntosh County, ND | 21 mi | 22% | 12% |
| Edmunds County, SD | 29 mi | 22% | 25% |
| Campbell County, SD | 38 mi | 18% | 13% |
| Dickey County, ND | 39 mi | 20% | 60% |
| Brown County, SD | 45 mi | 28% | 56% |
| Logan County, ND | 46 mi | 11% | 15% |
| Walworth County, SD | 48 mi | 26% | 10% |
| Faulk County, SD | 53 mi | 20% | 23% |
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