McClain County, Oklahoma
USDA's soil survey flags shrink-swell clay on 12% of McClain County's mapped land and a shallow water table under basements on 5%, both below the national shares of 15% and 29%. 100% of the county is in drought on the October 13, 2026 Drought Monitor map.
FEMA's flood data list 6 flood losses here since 2016. 27% of homes were built before 1980, against 50% nationally; the median home dates from 1997.
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 McClain County
| Expansive clay (limits slab homes) | 11.9% |
| High water table (limits basements) | 4.5% |
| Septic fields very limited | 64.0% |
| Clay swell (LEP, by area) | 3.6% |
| High-swell land (LEP 6%+) | 14.1% |
| Mapped soil | 372,480 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Grant | 19% | n/a |
| Stephenville | 11% | 0% |
| Nash | 11% | n/a |
| Lucien | 7% | n/a |
| Port | 5% | n/a |
| Renfrow | 5% | n/a |
How we count · survey areas OK087 (2025-08-29)
What the numbers mean here
Rain over the 12 months to August 2026: 22.08 in, 15.29 in below the 1991-2020 average year of 37.37 in.
USDA rates 64% of the land very limited for septic absorption fields.
With shrink-swell clay on 12% and a shallow water table on 5% of the land, the soil survey points to neither problem across most of McClain County; conditions still vary lot by lot.
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 52 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 | 86.5% |
| D3 extreme or worse | 72.7% |
| D4 exceptional | 26.7% |
Flood losses since 2016
6 flood losses since 2016, $101,596 paid. The worst year was 2022, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 3 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 37.37 in |
| 12 months to August 2026 | 22.08 in (-15.29) |
| 2025 | 40.82 in (+3.45) |
| Wettest year since 1895 | 2015: 62.10 in |
| Driest year since 1895 | 1901: 19.80 in |
| Days with 1 inch or more, normal at BLANCHARD 2 SSW (14 mi away) | 11.3 |
Homes
| Housing units | 17,630 |
| Median year built | 1997 |
| Built before 1980 | 27% |
| Built 2000 or later | 47% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $255,900 |
| Single-family detached | 83% |
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 |
|---|---|---|---|
| Cleveland County, OK | 15 mi | 21% | 5% |
| Garvin County, OK | 23 mi | 30% | 6% |
| Grady County, OK | 25 mi | 7% | 2% |
| Pottawatomie County, OK | 31 mi | 23% | 6% |
| Oklahoma County, OK | 37 mi | 21% | 3% |
| Murray County, OK | 43 mi | 29% | 7% |
| Stephens County, OK | 44 mi | 19% | 2% |
| Canadian County, OK | 47 mi | 20% | 4% |
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