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Rockwall, Texas
Inside Rockwall's city limits, shrink-swell clay limits houses without basements on 83% of mapped land, the 2nd-highest of 6 cities in Rockwall County. A shallow water table limits basements on under 1%.
That clay share is above Rockwall County's 72%. FEMA's flood data list 22 flood losses since 2016 in the 2 ZIP codes overlapping the city. Of its 19,328 homes, 9% were built before 1980; the median dates from 2003.
Data as of October 13, 2026 · sources · in Rockwall County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 2 overlapping ZIPs
of homes built before 1980
Foundation repair in Rockwall
Foundation repair in Rockwall: shrink-swell clay limits slab homes on 83% of Rockwall's mapped land, more than in 90% of Texas cities.
About 15,100 of Rockwall's 19,328 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 Rockwall city limits
| Expansive clay (limits slab homes) | 83.0% |
| High water table (limits basements) | 0.3% |
| Septic fields very limited | 68.4% |
| Clay swell (LEP, by area) | 11.3% |
| High-swell land (LEP 6%+) | 83.0% |
| Mapped soil | 19,244 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Houston Black | 44% | 91% |
| Heiden | 22% | 80% |
| Altoga | 13% | n/a |
| Ferris | 10% | n/a |
| Fairlie | 3% | 70% |
| Lewisville | 2% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 11.3% by land area here, and 83% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 83% of the mapped land.
Clay shrinks as it dries: 100% of Rockwall County is in drought on the latest map, and 83% of Rockwall's mapped land has shrink-swell clay.
USDA rates 68% of the land very limited for septic absorption fields.
Drought in Rockwall County
100% of Rockwall 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 Rockwall. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 75087 | 54% | 9 | $272,393 |
| 75032 | 41% | 13 | $267,391 |
Homes in Rockwall
| Housing units | 19,328 |
| Median year built | 2003 |
| Built before 1980 | 9% |
| Built 2000 or later | 62% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $411,700 |
| Single-family detached | 78% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Mobile City | 2 mi | 82% | 0% |
| Fate | 3 mi | 81% | under 1% |
| Heath | 5 mi | 82% | 3% |
| McLendon-Chisholm | 6 mi | 81% | 1% |
| Rowlett | 6 mi | 78% | under 1% |
| Lavon | 7 mi | 80% | under 1% |
| Royse City | 8 mi | 87% | 4% |
| Sachse | 9 mi | 81% | under 1% |
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