Alton, Texas
Inside Alton's city limits, shrink-swell clay limits houses without basements on under 1% of mapped land. A shallow water table limits basements on 1%.
That clay share is below Hidalgo County's 12%. FEMA's flood data list 58 flood losses since 2016 in ZIP code 78573 overlapping the city. Of its 6,029 homes, 9% were built before 1980; the median dates from 2006.
Data as of October 13, 2026 · sources · in Hidalgo 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 Alton
Foundation repair in Alton: shrink-swell clay limits slab homes on under 1% of Alton's mapped land.
About 3,800 of Alton's 6,029 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 Alton city limits
| Expansive clay (limits slab homes) | 0.1% |
| High water table (limits basements) | 1.3% |
| Septic fields very limited | 5.6% |
| Clay swell (LEP, by area) | 2.7% |
| High-swell land (LEP 6%+) | 0.1% |
| Mapped soil | 4,821 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Hidalgo | 48% | 0% |
| Brennan | 30% | n/a |
| Willacy | 4% | n/a |
| Racombes | 3% | n/a |
| Delmita | 2% | n/a |
| Raymondville | 2% | n/a |
What the numbers mean here
With shrink-swell clay on under 1% and a shallow water table on 1% of the land, the soil survey points to neither problem across most of Alton; conditions still vary lot by lot.
Drought in Hidalgo County
100% of Hidalgo 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 Alton. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78573 | 99% | 58 | $1.9 million |
Homes in Alton
| Housing units | 6,029 |
| Median year built | 2006 |
| Built before 1980 | 9% |
| Built 2000 or later | 65% |
| Owner-occupied | 55% |
| Median value, owner-occupied | $156,300 |
| Single-family detached | 63% |
Nearby cities
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