HomeSouth DakotaAurora County
Aurora County, South Dakota
Shrink-swell clay limits houses without basements on 42% of Aurora County's mapped land, a higher share than 88% of US counties. A shallow water table limits basements on 19%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 2 flood losses here since 2016. 69% 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 Aurora County
| Expansive clay (limits slab homes) | 42.0% |
| High water table (limits basements) | 19.4% |
| Septic fields very limited | 80.5% |
| Clay swell (LEP, by area) | 5.5% |
| High-swell land (LEP 6%+) | 43.0% |
| Mapped soil | 456,499 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Houdek | 28% | n/a |
| Dudley | 15% | n/a |
| Hoven | 7% | n/a |
| Ethan | 6% | n/a |
| Prosper | 5% | n/a |
| Clarno | 4% | 0% |
How we count · survey areas SD003 (2025-09-09)
What the numbers mean here
Clay swell averages a linear extensibility of 5.5% by land area here, and 43% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 42% of the mapped land.
On 19% of Aurora 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: 19.09 in, 5.27 in below the 1991-2020 average year of 24.36 in.
USDA rates 80% of the land very limited for septic absorption fields.
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 31 of the last 52 weeks; the most was 100% of its area, in 24 weeks, most recently on the August 25, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 63% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $99,980 paid. The worst year was 2019, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 2 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 24.36 in |
| 12 months to August 2026 | 19.09 in (-5.27) |
| 2025 | 22.87 in (-1.49) |
| Wettest year since 1895 | 2019: 39.91 in |
| Driest year since 1895 | 1934: 12.76 in |
| Days with 1 inch or more, normal at WHITE LAKE (5 mi away) | 5.7 |
Homes
| Housing units | 1,261 |
| Median year built | 1962 |
| Built before 1980 | 69% |
| Built 2000 or later | 20% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $151,900 |
| Single-family detached | 86% |
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 |
|---|---|---|---|
| Davison County, SD | 21 mi | 18% | 20% |
| Jerauld County, SD | 23 mi | 34% | 22% |
| Douglas County, SD | 25 mi | 33% | 21% |
| Brule County, SD | 26 mi | 43% | 12% |
| Sanborn County, SD | 32 mi | 28% | 40% |
| Charles Mix County, SD | 36 mi | 29% | 13% |
| Buffalo County, SD | 38 mi | 43% | 12% |
| Hanson County, SD | 39 mi | 21% | 25% |
Sources: USDA SSURGO (September 9, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status