Zapata County, Texas
Shrink-swell clay limits houses without basements on 17% of Zapata County's mapped land, a higher share than 67% 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 3 flood losses here since 2016. 28% of homes were built before 1980, against 50% nationally; the median home dates from 1992.
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 Zapata County
| Expansive clay (limits slab homes) | 17.4% |
| High water table (limits basements) | 0.1% |
| Septic fields very limited | 37.4% |
| Clay swell (LEP, by area) | 3.7% |
| High-swell land (LEP 6%+) | 17.4% |
| Mapped soil | 678,489 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Hebbronville | 17% | n/a |
| Brennan | 10% | n/a |
| Maverick | 10% | n/a |
| Aguilares | 7% | n/a |
| Copita | 7% | n/a |
| Brundage | 5% | n/a |
How we count · survey areas TX505 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 3.7% by land area here, and 17% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 17% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 17% of Zapata County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 15.27 in, 4.73 in below the 1991-2020 average year of 20.00 in.
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 44 of the last 52 weeks; the most was 100% of its area, in 35 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 | 10.1% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
3 flood losses since 2016, $21,222 paid. The worst year was 2023, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 2 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 20.00 in |
| 12 months to August 2026 | 15.27 in (-4.73) |
| 2025 | 13.44 in (-6.56) |
| Wettest year since 1895 | 1973: 35.83 in |
| Driest year since 1895 | 1917: 7.12 in |
| Days with 1 inch or more, normal at FALCON DAM (30 mi away) | 6.2 |
Homes
| Housing units | 6,255 |
| Median year built | 1992 |
| Built before 1980 | 28% |
| Built 2000 or later | 26% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $97,100 |
| Single-family detached | 60% |
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 |
|---|---|---|---|
| Jim Hogg County, TX | 27 mi | under 1% | under 1% |
| Starr County, TX | 42 mi | 14% | 1% |
| Webb County, TX | 53 mi | 33% | under 1% |
| Brooks County, TX | 60 mi | 1% | 9% |
| Duval County, TX | 63 mi | 4% | under 1% |
| Hidalgo County, TX | 75 mi | 12% | 6% |
| Jim Wells County, TX | 84 mi | 27% | 19% |
| La Salle County, TX | 94 mi | 35% | 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