HomeTexasHidalgo CountyMcAllen
McAllen, Texas
Inside McAllen's city limits, shrink-swell clay limits houses without basements on 18% of mapped land. A shallow water table limits basements on 2%.
That clay share is above Hidalgo County's 12%. FEMA's flood data list 228 flood losses since 2016 in the 3 ZIP codes overlapping the city. Of its 55,385 homes, 25% were built before 1980; the median dates from 1995.
Data as of September 22, 2026 · sources · in Hidalgo County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 3 overlapping ZIPs
of homes built before 1980
Soil under McAllen city limits
| Expansive clay (limits slab homes) | 17.7% |
| High water table (limits basements) | 1.7% |
| Septic fields very limited | 22.9% |
| Clay swell (LEP, by area) | 4.6% |
| High-swell land (LEP 6%+) | 17.7% |
| Urban land, not rated | 6.9% |
| Mapped soil | 40,159 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Hidalgo | 43% | 0% |
| Brennan | 10% | n/a |
| Runn | 10% | n/a |
| Harlingen | 5% | n/a |
| Raymondville | 4% | n/a |
| Racombes | 3% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 4.6% by land area here, and 18% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 18% of the mapped land.
Clay shrinks as it dries: 100% of Hidalgo County is in drought on the latest map, and 18% of McAllen's mapped land has shrink-swell clay.
Drought in Hidalgo County
100% of Hidalgo County is in drought (D1 or worse) on the September 22, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap McAllen. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78503 | 28% | 91 | $4.0 million |
| 78504 | 28% | 54 | $2.8 million |
| 78501 | 25% | 83 | $2.1 million |
Homes in McAllen
| Housing units | 55,385 |
| Median year built | 1995 |
| Built before 1980 | 25% |
| Built 2000 or later | 42% |
| Owner-occupied | 60% |
| Median value, owner-occupied | $190,400 |
| Single-family detached | 64% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Palmhurst | 4 mi | 0% | 1% |
| Mission | 5 mi | 25% | 5% |
| Pharr | 5 mi | 46% | 2% |
| Alton | 6 mi | under 1% | 1% |
| San Juan | 6 mi | 32% | 1% |
| Granjeno | 7 mi | 57% | 0% |
| Hidalgo | 8 mi | 52% | 1% |
| Palmview | 8 mi | 7% | 1% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (September 22, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status