Seminole County, Oklahoma
A shallow water table limits basements on 25% of Seminole County's mapped land. Shrink-swell clay limits houses without basements on 17%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 11 flood losses here since 2016. 56% of homes were built before 1980, against 50% nationally; the median home dates from 1976.
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 Seminole County
| Expansive clay (limits slab homes) | 16.8% |
| High water table (limits basements) | 25.0% |
| Septic fields very limited | 84.3% |
| Clay swell (LEP, by area) | 3.7% |
| High-swell land (LEP 6%+) | 23.6% |
| Mapped soil | 409,862 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Stephenville | 23% | 0% |
| Seminole | 10% | n/a |
| Darnell | 10% | n/a |
| Gowton | 7% | n/a |
| Niotaze | 7% | n/a |
| Konawa | 7% | n/a |
How we count · survey areas OK133 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 3.7% by land area here, and 24% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 17% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 17% of Seminole County's mapped land has shrink-swell clay.
On 25% of Seminole 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: 29.67 in, 11.84 in below the 1991-2020 average year of 41.51 in.
USDA rates 84% 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 47 of the last 52 weeks; the most was 100% of its area, in 27 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 | 77.6% |
| D3 extreme or worse | 33% |
| D4 exceptional | 0% |
Flood losses since 2016
11 flood losses since 2016, $637,445 paid. The worst year was 2024, with 6.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 1 |
| 2024 | 6 |
| 2025 | 2 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 41.51 in |
| 12 months to August 2026 | 29.67 in (-11.84) |
| 2025 | 45.00 in (+3.49) |
| Wettest year since 1895 | 2015: 68.81 in |
| Driest year since 1895 | 1910: 22.53 in |
| Days with 1 inch or more, normal at SEMINOLE (6 mi away) | 13.4 |
Homes
| Housing units | 10,838 |
| Median year built | 1976 |
| Built before 1980 | 56% |
| Built 2000 or later | 20% |
| Owner-occupied | 71% |
| Median value, owner-occupied | $99,500 |
| Single-family detached | 77% |
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 |
|---|---|---|---|
| Pottawatomie County, OK | 20 mi | 23% | 6% |
| Hughes County, OK | 21 mi | 31% | 43% |
| Okfuskee County, OK | 26 mi | 30% | 39% |
| Pontotoc County, OK | 31 mi | 28% | 15% |
| Lincoln County, OK | 41 mi | 27% | 10% |
| Cleveland County, OK | 41 mi | 21% | 5% |
| Coal County, OK | 44 mi | 54% | 71% |
| McClain County, OK | 49 mi | 12% | 5% |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status