Stephens County, Oklahoma
Shrink-swell clay limits houses without basements on 19% of Stephens County's mapped land, a higher share than 69% of US counties. A shallow water table limits basements on 2%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 13 flood losses here since 2016. 60% of homes were built before 1980, against 50% nationally; the median home dates from 1975.
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 Stephens County
| Expansive clay (limits slab homes) | 19.5% |
| High water table (limits basements) | 1.8% |
| Septic fields very limited | 75.2% |
| Clay swell (LEP, by area) | 3.8% |
| High-swell land (LEP 6%+) | 19.7% |
| Mapped soil | 570,246 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Stephenville | 22% | 0% |
| Zaneis | 13% | n/a |
| Chickasha | 10% | n/a |
| Port | 8% | n/a |
| Newalla | 6% | n/a |
| Littleaxe | 6% | n/a |
How we count · survey areas OK137 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 3.8% by land area here, and 20% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 19% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 19% of Stephens County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 24.44 in, 10.81 in below the 1991-2020 average year of 35.25 in.
USDA rates 75% 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 46 of the last 52 weeks; the most was 100% of its area, in 37 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 | 100% |
| D3 extreme or worse | 90.2% |
| D4 exceptional | 16.6% |
Flood losses since 2016
13 flood losses since 2016, $402,112 paid. The worst year was 2025, with 5.
| Year | Flood losses |
|---|---|
| 2016 | 5 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 5 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 35.25 in |
| 12 months to August 2026 | 24.44 in (-10.81) |
| 2025 | 40.98 in (+5.73) |
| Wettest year since 1895 | 1908: 52.76 in |
| Driest year since 1895 | 1939: 18.68 in |
| Days with 1 inch or more, normal at DUNCAN (6 mi away) | 11.5 |
Homes
| Housing units | 20,323 |
| Median year built | 1975 |
| Built before 1980 | 60% |
| Built 2000 or later | 14% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $145,300 |
| Single-family detached | 82% |
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 |
|---|---|---|---|
| Jefferson County, OK | 26 mi | 17% | 1% |
| Cotton County, OK | 32 mi | 54% | 4% |
| Garvin County, OK | 35 mi | 30% | 6% |
| Carter County, OK | 36 mi | 23% | 3% |
| Grady County, OK | 37 mi | 7% | 2% |
| Comanche County, OK | 37 mi | 38% | 4% |
| McClain County, OK | 44 mi | 12% | 5% |
| Murray County, OK | 45 mi | 29% | 7% |
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