Webb County, Texas
Shrink-swell clay limits houses without basements on 33% of Webb County's mapped land, a higher share than 83% of US counties. A shallow water table limits basements on under 1%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 40 flood losses here since 2016, 0% of them in buildings with basements. 24% 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 Webb County
| Expansive clay (limits slab homes) | 33.2% |
| High water table (limits basements) | 0.2% |
| Septic fields very limited | 69.2% |
| Clay swell (LEP, by area) | 6.3% |
| High-swell land (LEP 6%+) | 33.2% |
| Mapped soil | 2,154,163 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Catarina | 13% | n/a |
| Copita | 9% | n/a |
| Maverick | 9% | n/a |
| Montell | 7% | n/a |
| Moglia | 6% | n/a |
| Brundage | 5% | n/a |
How we count · survey areas TX479 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 6.3% by land area here, and 33% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 33% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 33% of Webb County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 16.21 in, 4.83 in below the 1991-2020 average year of 21.04 in.
USDA rates 69% 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 34 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 | 39.6% |
| D4 exceptional | 0% |
Flood losses since 2016
40 flood losses since 2016, $983,818 paid. The worst year was 2017, with 24. Foundations of the buildings, where recorded: 87% slabs, 4% crawl spaces, 9% elevated.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 24 |
| 2018 | 2 |
| 2019 | 3 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 5 |
| 2023 | 2 |
| 2024 | 1 |
| 2025 | 1 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 21.04 in |
| 12 months to August 2026 | 16.21 in (-4.83) |
| 2025 | 13.62 in (-7.42) |
| Wettest year since 1895 | 1919: 42.41 in |
| Driest year since 1895 | 1917: 6.67 in |
| Days with 1 inch or more, normal at LAREDO 2 (16 mi away) | 5.8 |
Homes
| Housing units | 88,176 |
| Median year built | 1997 |
| Built before 1980 | 24% |
| Built 2000 or later | 43% |
| Owner-occupied | 65% |
| Median value, owner-occupied | $189,900 |
| Single-family detached | 68% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Webb County
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| La Salle County, TX | 44 mi | 35% | under 1% |
| Duval County, TX | 51 mi | 4% | under 1% |
| Zapata County, TX | 53 mi | 17% | under 1% |
| Dimmit County, TX | 54 mi | 30% | under 1% |
| Jim Hogg County, TX | 60 mi | under 1% | under 1% |
| McMullen County, TX | 64 mi | 35% | under 1% |
| Jim Wells County, TX | 76 mi | 27% | 19% |
| Frio County, TX | 79 mi | 10% | under 1% |
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