Tillman County, Oklahoma
Shrink-swell clay limits houses without basements on 47% of Tillman County's mapped land, a higher share than 90% 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 no flood losses here since 2016. 83% of homes were built before 1980, against 50% nationally; the median home dates from 1963.
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 Tillman County
| Expansive clay (limits slab homes) | 46.7% |
| High water table (limits basements) | 1.6% |
| Septic fields very limited | 75.8% |
| Clay swell (LEP, by area) | 5.4% |
| High-swell land (LEP 6%+) | 42.9% |
| Mapped soil | 580,282 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Tipton | 11% | n/a |
| Foard | 9% | n/a |
| Tillman | 9% | 93% |
| Vernon | 8% | n/a |
| Hollister | 6% | n/a |
| Devol | 5% | n/a |
How we count · survey areas OK141 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 5.4% 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 47% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 47% of Tillman County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 17.37 in, 11.09 in below the 1991-2020 average year of 28.46 in.
USDA rates 76% 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 52 of the last 52 weeks; the most was 100% of its area, in 42 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 | 100% |
| D4 exceptional | 92.8% |
Flood losses since 2016
FEMA's flood data list no flood losses in Tillman County since 2016.
Rain
| Average year, 1991-2020 | 28.46 in |
| 12 months to August 2026 | 17.37 in (-11.09) |
| 2025 | 31.17 in (+2.71) |
| Wettest year since 1895 | 1941: 43.09 in |
| Driest year since 1895 | 2011: 14.14 in |
| Days with 1 inch or more, normal at HEADRICK (21 mi away) | 8.1 |
Homes
| Housing units | 3,748 |
| Median year built | 1963 |
| Built before 1980 | 83% |
| Built 2000 or later | 6% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $79,800 |
| Single-family detached | 89% |
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 |
|---|---|---|---|
| Wilbarger County, TX | 27 mi | 41% | under 1% |
| Wichita County, TX | 29 mi | 43% | under 1% |
| Jackson County, OK | 31 mi | 35% | 10% |
| Cotton County, OK | 32 mi | 54% | 4% |
| Comanche County, OK | 33 mi | 38% | 4% |
| Kiowa County, OK | 38 mi | 54% | 1% |
| Hardeman County, TX | 47 mi | 34% | 1% |
| Greer County, OK | 53 mi | 26% | 3% |
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