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Red Oak, Texas
Inside Red Oak's city limits, shrink-swell clay limits houses without basements on 81% of mapped land, higher than 87% of Texas cities. A shallow water table limits basements on under 1%.
That clay share is above Ellis County's 72%. FEMA's flood data list 38 flood losses since 2016 in ZIP code 75154 overlapping the city. Of its 5,540 homes, 13% were built before 1980; the median dates from 2007.
Data as of October 13, 2026 · sources · in Ellis 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 Red Oak
Foundation repair in Red Oak: shrink-swell clay limits slab homes on 81% of Red Oak's mapped land, more than in 87% of Texas cities.
About 4,700 of Red Oak's 5,540 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 Red Oak city limits
| Expansive clay (limits slab homes) | 81.2% |
| High water table (limits basements) | 0.1% |
| Septic fields very limited | 84.9% |
| Clay swell (LEP, by area) | 8.3% |
| High-swell land (LEP 6%+) | 45.0% |
| Mapped soil | 12,487 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Austin | 33% | 93% |
| Houston Black | 31% | 91% |
| Branyon | 9% | 92% |
| Heiden | 5% | 80% |
| Burleson | 4% | 84% |
| Frio | 4% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 8.3% by land area here, and 45% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 81% of the mapped land.
Clay shrinks as it dries: 100% of Ellis County is in drought on the latest map, and 81% of Red Oak's mapped land has shrink-swell clay.
USDA rates 85% of the land very limited for septic absorption fields.
Drought in Ellis County
100% of Ellis 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 Red Oak. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 75154 | 90% | 38 | $3.6 million |
Homes in Red Oak
| Housing units | 5,540 |
| Median year built | 2007 |
| Built before 1980 | 13% |
| Built 2000 or later | 69% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $366,100 |
| Single-family detached | 84% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Pecan Hill | 2 mi | 78% | under 1% |
| Oak Leaf | 4 mi | 77% | under 1% |
| Glenn Heights | 5 mi | 75% | under 1% |
| Lancaster | 6 mi | 68% | under 1% |
| Ovilla | 6 mi | 56% | under 1% |
| Ferris | 7 mi | 81% | under 1% |
| DeSoto | 8 mi | 49% | under 1% |
| Waxahachie | 8 mi | 73% | 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