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San Patricio, Texas
Inside San Patricio's city limits, shrink-swell clay limits houses without basements on 39% of mapped land, the 5th-highest of 11 cities in San Patricio County. A shallow water table limits basements on 18%, the 3rd-highest of 11 cities in San Patricio County.
That clay share is below San Patricio County's 58%. FEMA's flood data list no flood losses since 2016 in ZIP code 78368 overlapping the city. Of its 199 homes, 30% were built before 1980; the median dates from 1988.
Data as of October 13, 2026 · sources · in San Patricio County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Foundation repair in San Patricio
Foundation repair in San Patricio: shrink-swell clay limits slab homes on 39% of San Patricio's mapped land.
About 100 of San Patricio's 199 homes are detached houses.
| Who designs the repair | The ASCE Texas Section's repair guidelines say a Texas-licensed engineer should evaluate the foundation and design the repair (2022 guidelines) |
| Prices | Cost guide ranges compared |
Soil under San Patricio city limits
| Expansive clay (limits slab homes) | 39.2% |
| High water table (limits basements) | 18.2% |
| Septic fields very limited | 54.4% |
| Clay swell (LEP, by area) | 5.9% |
| High-swell land (LEP 6%+) | 39.2% |
| Mapped soil | 2,492 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Willacy | 23% | n/a |
| Aransas | 14% | n/a |
| Victoria | 12% | 99% |
| Raymondville | 11% | n/a |
| Pharr | 7% | n/a |
| Pettus | 5% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 5.9% by land area here, and 39% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 39% of the mapped land.
Clay shrinks as it dries: 100% of San Patricio County is in drought on the latest map, and 39% of San Patricio's mapped land has shrink-swell clay.
On 18% of San Patricio's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 54% of the land very limited for septic absorption fields.
Drought in San Patricio County
100% of San Patricio County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap San Patricio. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78368 | 100% | 0 | $0 |
Homes in San Patricio
| Housing units | 199 |
| Median year built | 1988 |
| Built before 1980 | 30% |
| Built 2000 or later | 39% |
| Owner-occupied | 89% |
| Median value, owner-occupied | $134,400 |
| Single-family detached | 68% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Mathis | 8 mi | 67% | 1% |
| Lake City | 10 mi | 1% | 0% |
| Lakeside | 10 mi | 25% | 7% |
| Orange Grove | 10 mi | 82% | under 1% |
| Odem | 11 mi | 30% | 3% |
| Robstown | 15 mi | 90% | 2% |
| Agua Dulce | 16 mi | 97% | 1% |
| Sinton | 17 mi | 15% | 4% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status