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Pasadena, Texas
Inside Pasadena's city limits, shrink-swell clay limits houses without basements on 53% of mapped land, higher than 60% of Texas cities. A shallow water table limits basements on 37%.
That clay share is above Harris County's 25%. FEMA's flood data list 2,380 flood losses since 2016 in the 7 ZIP codes overlapping the city. Of its 53,756 homes, 57% were built before 1980; the median dates from 1977.
Data as of September 22, 2026 · sources · in Harris County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 7 overlapping ZIPs
of homes built before 1980
Soil under Pasadena city limits
| Expansive clay (limits slab homes) | 53.2% |
| High water table (limits basements) | 36.7% |
| Septic fields very limited | 77.4% |
| Clay swell (LEP, by area) | 10.0% |
| High-swell land (LEP 6%+) | 53.2% |
| Urban land, not rated | 19.3% |
| Mapped soil | 28,625 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Lake Charles | 31% | 97% |
| Bernard | 17% | 43% |
| Beaumont | 6% | n/a |
| Verland | 4% | n/a |
| Mocarey | 4% | n/a |
| Addicks | 2% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 10.0% by land area here, and 53% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 53% of the mapped land.
Clay shrinks as it dries: 16.5% of Harris County is in drought on the latest map, and 53% of Pasadena's mapped land has shrink-swell clay.
On 37% of Pasadena's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 77% of the land very limited for septic absorption fields.
Drought in Harris County
16.5% of Harris 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 Pasadena. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 77505 | 19% | 428 | $28.7 million |
| 77506 | 17% | 200 | $16.7 million |
| 77503 | 14% | 208 | $9.5 million |
| 77502 | 13% | 460 | $32.3 million |
| 77504 | 11% | 190 | $11.5 million |
| 77586 | 7% | 523 | $20.8 million |
| 77058 | 6% | 371 | $18.4 million |
Homes in Pasadena
| Housing units | 53,756 |
| Median year built | 1977 |
| Built before 1980 | 57% |
| Built 2000 or later | 17% |
| Owner-occupied | 55% |
| Median value, owner-occupied | $209,600 |
| Single-family detached | 58% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Deer Park | 3 mi | 58% | 74% |
| South Houston | 5 mi | 53% | 6% |
| La Porte | 6 mi | 74% | 39% |
| Galena Park | 8 mi | 67% | 59% |
| Taylor Lake Village | 8 mi | 41% | 41% |
| Shoreacres | 8 mi | 68% | 39% |
| Nassau Bay | 9 mi | 31% | 30% |
| El Lago | 9 mi | 47% | 41% |
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