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Rio Hondo, Texas
Inside Rio Hondo's city limits, shrink-swell clay limits houses without basements on 39% of mapped land. A shallow water table limits basements on 21%.
That clay share is above Cameron County's 29%. FEMA's flood data list 883 flood losses since 2016 in the 2 ZIP codes overlapping the city. Of its 794 homes, 41% were built before 1980; the median dates from 1986.
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 Rio Hondo
Foundation repair in Rio Hondo: shrink-swell clay limits slab homes on 39% of Rio Hondo's mapped land.
About 500 of Rio Hondo's 794 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 Rio Hondo city limits
| Expansive clay (limits slab homes) | 38.7% |
| High water table (limits basements) | 21.2% |
| Septic fields very limited | 43.6% |
| Clay swell (LEP, by area) | 7.5% |
| High-swell land (LEP 6%+) | 38.7% |
| Urban land, not rated | 8.1% |
| Mapped soil | 1,161 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Raymondville | 31% | n/a |
| Lyford | 19% | n/a |
| Mercedes | 11% | n/a |
| Racombes | 10% | n/a |
| Hidalgo | 8% | 0% |
| Willacy | 3% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 7.5% 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: 83.8% of Cameron County is in drought on the latest map, and 39% of Rio Hondo's mapped land has shrink-swell clay.
On 21% of Rio Hondo's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
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 Rio Hondo. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78583 | 70% | 35 | $1.7 million |
| 78550 | 30% | 848 | $50.2 million |
Homes in Rio Hondo
| Housing units | 794 |
| Median year built | 1986 |
| Built before 1980 | 41% |
| Built 2000 or later | 24% |
| Owner-occupied | 58% |
| Median value, owner-occupied | $104,000 |
| Single-family detached | 65% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Harlingen | 8 mi | 62% | 1% |
| San Benito | 8 mi | 63% | 4% |
| Combes | 9 mi | 26% | 2% |
| Primera | 11 mi | 18% | 3% |
| Palm Valley | 11 mi | 18% | 4% |
| Indian Lake | 11 mi | 15% | 0% |
| Los Fresnos | 12 mi | 45% | 10% |
| Rangerville | 13 mi | 56% | 5% |
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