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Sullivan City, Texas
Inside Sullivan City's city limits, shrink-swell clay limits houses without basements on 3% of mapped land. A shallow water table limits basements on 4%, the 3rd-highest of 22 cities in Hidalgo County.
That clay share is below Hidalgo County's 12%. FEMA's flood data list 14 flood losses since 2016 in ZIP code 78595 overlapping the city. Of its 1,297 homes, 15% were built before 1980; the median dates from 1997.
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 Sullivan City
Foundation repair in Sullivan City: shrink-swell clay limits slab homes on 3% of Sullivan City's mapped land.
About 1,200 of Sullivan City's 1,297 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 Sullivan City city limits
| Expansive clay (limits slab homes) | 2.6% |
| High water table (limits basements) | 3.6% |
| Septic fields very limited | 39.8% |
| Clay swell (LEP, by area) | 2.1% |
| High-swell land (LEP 6%+) | 2.6% |
| Mapped soil | 2,295 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| McAllen | 44% | n/a |
| Ramadero | 6% | n/a |
| Brennan | 3% | n/a |
| Rio | 3% | n/a |
| Reynosa | 2% | n/a |
| Runn | 2% | n/a |
What the numbers mean here
With shrink-swell clay on 3% and a shallow water table on 4% of the land, the soil survey points to neither problem across most of Sullivan City; 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 Sullivan City. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78595 | 99% | 14 | $587,992 |
Homes in Sullivan City
| Housing units | 1,297 |
| Median year built | 1997 |
| Built before 1980 | 15% |
| Built 2000 or later | 42% |
| Owner-occupied | 88% |
| Median value, owner-occupied | $94,600 |
| Single-family detached | 90% |
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