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Portland, Texas
Inside Portland's city limits, shrink-swell clay limits houses without basements on 63% of mapped land, the 4th-highest of 11 cities in San Patricio County. A shallow water table limits basements on 7%, the 5th-highest of 11 cities in San Patricio County.
That clay share is above San Patricio County's 58%. FEMA's flood data list 96 flood losses since 2016 in the 2 ZIP codes overlapping the city. Of its 8,542 homes, 43% were built before 1980; the median dates from 1987.
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 2 overlapping ZIPs
of homes built before 1980
Foundation repair in Portland
Foundation repair in Portland: shrink-swell clay limits slab homes on 63% of Portland's mapped land, more than in 68% of Texas cities.
About 6,100 of Portland's 8,542 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 Portland city limits
| Expansive clay (limits slab homes) | 63.1% |
| High water table (limits basements) | 6.7% |
| Septic fields very limited | 69.0% |
| Clay swell (LEP, by area) | 13.6% |
| High-swell land (LEP 6%+) | 63.1% |
| Mapped soil | 9,784 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Victoria | 44% | 99% |
| Raymondville | 11% | n/a |
| Calallen | 5% | n/a |
| Banquete | 4% | n/a |
| Monteola | 3% | n/a |
| Dianola | 3% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 13.6% by land area here, and 63% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 63% of the mapped land.
Clay shrinks as it dries: 100% of San Patricio County is in drought on the latest map, and 63% of Portland's mapped land has shrink-swell clay.
USDA rates 69% 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 Portland. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78374 | 74% | 70 | $491,662 |
| 78390 | 21% | 26 | $276,653 |
Homes in Portland
| Housing units | 8,542 |
| Median year built | 1987 |
| Built before 1980 | 43% |
| Built 2000 or later | 35% |
| Owner-occupied | 63% |
| Median value, owner-occupied | $234,800 |
| Single-family detached | 71% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Gregory | 3 mi | 76% | 2% |
| Taft | 7 mi | 83% | 2% |
| Ingleside | 8 mi | 27% | 45% |
| Ingleside on the Bay | 8 mi | 0% | 26% |
| Aransas Pass | 13 mi | 3% | 29% |
| Corpus Christi | 13 mi | 17% | 8% |
| Sinton | 15 mi | 15% | 4% |
| Port Aransas | 16 mi | 1% | 49% |
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