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Harlingen, Texas
Inside Harlingen's city limits, shrink-swell clay limits houses without basements on 62% of mapped land, the 2nd-highest of 19 cities in Cameron County. A shallow water table limits basements on 1%.
That clay share is above Cameron County's 29%. FEMA's flood data list 1,604 flood losses since 2016 in the 2 ZIP codes overlapping the city. Of its 29,595 homes, 36% were built before 1980; the median dates from 1988.
Data as of October 13, 2026 · sources · in Cameron 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 Harlingen
Foundation repair in Harlingen: shrink-swell clay limits slab homes on 62% of Harlingen's mapped land, more than in 67% of Texas cities.
About 17,700 of Harlingen's 29,595 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 Harlingen city limits
| Expansive clay (limits slab homes) | 61.7% |
| High water table (limits basements) | 1.3% |
| Septic fields very limited | 70.2% |
| Clay swell (LEP, by area) | 11.0% |
| High-swell land (LEP 6%+) | 61.7% |
| Urban land, not rated | 8.7% |
| Mapped soil | 26,956 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Mercedes | 32% | n/a |
| Raymondville | 26% | n/a |
| Hidalgo | 9% | 0% |
| Racombes | 8% | n/a |
| Willacy | 6% | n/a |
| Harlingen | 5% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 11.0% by land area here, and 62% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 62% of the mapped land.
Clay shrinks as it dries: 83.8% of Cameron County is in drought on the latest map, and 62% of Harlingen's mapped land has shrink-swell clay.
USDA rates 70% of the land very limited for septic absorption fields.
Drought in Cameron County
83.8% of Cameron 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 Harlingen. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78550 | 61% | 848 | $50.2 million |
| 78552 | 35% | 756 | $55.7 million |
Homes in Harlingen
| Housing units | 29,595 |
| Median year built | 1988 |
| Built before 1980 | 36% |
| Built 2000 or later | 28% |
| Owner-occupied | 56% |
| Median value, owner-occupied | $140,600 |
| Single-family detached | 60% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Palm Valley | 4 mi | 18% | 4% |
| Primera | 4 mi | 18% | 3% |
| Combes | 4 mi | 26% | 2% |
| San Benito | 5 mi | 63% | 4% |
| Rangerville | 6 mi | 56% | 5% |
| Rio Hondo | 8 mi | 39% | 21% |
| La Feria | 8 mi | 24% | under 1% |
| Santa Rosa | 9 mi | 50% | 2% |
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