Wilson County, Texas
Shrink-swell clay limits houses without basements on 36% of Wilson County's mapped land, a higher share than 85% 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 6 flood losses here since 2016. 17% of homes were built before 1980, against 50% nationally; the median home dates from 2000.
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 Wilson County
| Expansive clay (limits slab homes) | 36.2% |
| High water table (limits basements) | 1.8% |
| Septic fields very limited | 81.1% |
| Clay swell (LEP, by area) | 5.1% |
| High-swell land (LEP 6%+) | 26.6% |
| Mapped soil | 516,300 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Wilco | 10% | n/a |
| Miguel | 10% | n/a |
| Floresville | 9% | n/a |
| Aluf | 9% | n/a |
| Elmendorf | 6% | n/a |
| Hitilo | 5% | n/a |
How we count · survey areas TX493 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 5.1% by land area here, and 27% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 36% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 36% of Wilson County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 25.78 in, 5.60 in below the 1991-2020 average year of 31.38 in.
USDA rates 81% 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 43 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 | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
6 flood losses since 2016, $39,493 paid. The worst year was 2021, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 3 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 3 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 31.38 in |
| 12 months to August 2026 | 25.78 in (-5.60) |
| 2025 | 20.74 in (-10.64) |
| Wettest year since 1895 | 1973: 50.50 in |
| Driest year since 1895 | 1917: 10.10 in |
| Days with 1 inch or more, normal at STOCKDALE 6N (12 mi away) | 10.8 |
Homes
| Housing units | 19,480 |
| Median year built | 2000 |
| Built before 1980 | 17% |
| Built 2000 or later | 49% |
| Owner-occupied | 85% |
| Median value, owner-occupied | $321,300 |
| Single-family detached | 67% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Wilson County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Floresville | 16% | under 1% | 3,324 |
| La Vernia | 7% | 0% | 536 |
| Poth | 51% | 1% | 659 |
| Stockdale | 8% | 0% | 490 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Karnes County, TX | 23 mi | 52% | under 1% |
| Guadalupe County, TX | 29 mi | 52% | 8% |
| Bexar County, TX | 32 mi | 51% | under 1% |
| Atascosa County, TX | 33 mi | 34% | under 1% |
| Gonzales County, TX | 41 mi | 55% | 5% |
| DeWitt County, TX | 44 mi | 27% | 17% |
| Comal County, TX | 45 mi | 19% | under 1% |
| Caldwell County, TX | 53 mi | 59% | 6% |
Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status