HomeTexasTom Green CountySan Angelo
San Angelo, Texas
Inside San Angelo's city limits, shrink-swell clay limits houses without basements on 35% of mapped land. A shallow water table limits basements on under 1%.
That clay share is below Tom Green County's 43%. FEMA's flood data list 85 flood losses since 2016 in the 6 ZIP codes overlapping the city. Of its 44,176 homes, 53% were built before 1980; the median dates from 1978.
Data as of September 22, 2026 · sources · in Tom Green County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 6 overlapping ZIPs
of homes built before 1980
Soil under San Angelo city limits
| Expansive clay (limits slab homes) | 34.8% |
| High water table (limits basements) | 0.3% |
| Septic fields very limited | 76.3% |
| Clay swell (LEP, by area) | 5.2% |
| High-swell land (LEP 6%+) | 32.5% |
| Urban land, not rated | 8.7% |
| Mapped soil | 39,994 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Angelo | 23% | n/a |
| Cho | 17% | n/a |
| Mereta | 10% | n/a |
| Tulia | 9% | n/a |
| Rioconcho | 7% | n/a |
| Slaughter | 4% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 5.2% by land area here, and 32% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 35% of the mapped land.
Clay shrinks as it dries: 100% of Tom Green County is in drought on the latest map, and 35% of San Angelo's mapped land has shrink-swell clay.
USDA rates 76% of the land very limited for septic absorption fields.
Drought in Tom Green County
100% of Tom Green County is in drought (D1 or worse) on the September 22, 2026 map.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap San Angelo. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 76904 | 35% | 6 | $211,761 |
| 76903 | 33% | 37 | $3.1 million |
| 76905 | 16% | 15 | $1.0 million |
| 76901 | 13% | 27 | $1.1 million |
| 76908 | 3% | 0 | $0 |
| 76909 | under 1% | 0 | $0 |
Homes in San Angelo
| Housing units | 44,176 |
| Median year built | 1978 |
| Built before 1980 | 53% |
| Built 2000 or later | 20% |
| Owner-occupied | 61% |
| Median value, owner-occupied | $187,600 |
| Single-family detached | 70% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Miles | 19 mi | 52% | 4% |
| Mertzon | 25 mi | 15% | 0% |
| Paint Rock | 31 mi | 29% | 0% |
| Robert Lee | 32 mi | 25% | under 1% |
| Bronte | 32 mi | 23% | under 1% |
| Ballinger | 36 mi | 12% | under 1% |
| Eden | 39 mi | 36% | 0% |
| Eldorado | 41 mi | 70% | 0% |
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