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Dallas, Texas
Inside Dallas' city limits, shrink-swell clay limits houses without basements on 37% of mapped land. A shallow water table limits basements on 5%.
That clay share is below Dallas County's 51%. FEMA's flood data list 342 flood losses since 2016 in the 48 ZIP codes overlapping the city. Of its 590,237 homes, 48% were built before 1980; the median dates from 1981.
Data as of November 3, 2026 · sources · in Dallas County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 48 overlapping ZIPs
of homes built before 1980
Foundation repair in Dallas
Foundation repair in Dallas: shrink-swell clay limits slab homes on 37% of Dallas' mapped land.
The city lists a permit for the work, and Angi (October 7, 2025) publishes a range of $3,338 to $7,118 a job.
About 243,800 of Dallas' 590,237 homes are detached houses.
| City permit | Dallas issues foundation repair permits at its Permit Center and at district Building Inspection offices. (City of Dallas, Development Services / Building Inspection, read October 2, 2026) |
| 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) |
| Watering the foundation | Dallas's drought plan defines foundation watering as a hand-held hose, soaker hose or drip line within 24 inches of the foundation, allowed any day and any time in Stages 1 and 2. (City of Dallas, Dallas Water Utilities) |
| Prices | Angi, October 7, 2025 · cost guide ranges compared |
Soil under Dallas city limits
| Expansive clay (limits slab homes) | 37.5% |
| High water table (limits basements) | 5.4% |
| Septic fields very limited | 70.7% |
| Clay swell (LEP, by area) | 8.5% |
| High-swell land (LEP 6%+) | 35.8% |
| Urban land, not rated | 21.4% |
| Mapped soil | 245,396 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Houston Black | 8% | 91% |
| Austin | 8% | 93% |
| Trinity | 7% | n/a |
| Eddy | 6% | 0% |
| Stephen | 5% | n/a |
| Frio | 3% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 8.5% by land area here, and 36% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 37% of the mapped land.
Clay shrinks as it dries: 100% of Dallas County is in drought on the latest map, and 37% of Dallas' mapped land has shrink-swell clay.
USDA rates 71% of the land very limited for septic absorption fields.
Dallas covers 339.6 square miles of land and counts 590,237 housing units, about 1,738 per square mile.
42% of Dallas' occupied homes are owner-occupied, and the median owner-occupied home is valued at $320,700; 26% of all homes in the city date from 2000 or later.
The largest soil series under Dallas is Houston Black, on 8% of the mapped land, followed by Austin at 8%.
USDA's soil survey maps 245,396 acres inside Dallas' city limits.
Drought in Dallas County
100% of Dallas County is in drought (D1 or worse) on the November 3, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap Dallas. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 75217 | 8% | 6 | $15,865 |
| 75241 | 7% | 3 | $37,919 |
| 75211 | 5% | 3 | $13,694 |
| 75216 | 4% | 1 | $1,202 |
| 75236 | 4% | 1 | $0 |
| 75253 | 4% | 15 | $749,207 |
| 75229 | 4% | 41 | $2.4 million |
| 75227 | 3% | 10 | $129,811 |
| 75220 | 3% | 9 | $305,121 |
| 75228 | 3% | 3 | $30,211 |
| 75212 | 3% | 2 | $31,583 |
| 75243 | 3% | 16 | $941,055 |
| 75215 | 2% | 0 | $0 |
| 75232 | 2% | 8 | $194,170 |
| 75214 | 2% | 12 | $317,572 |
| 75248 | 2% | 10 | $40,064 |
| 75230 | 2% | 26 | $1.6 million |
| 75218 | 2% | 6 | $225,661 |
| 75235 | 2% | 0 | $0 |
| 75237 | 2% | 0 | $0 |
| 75238 | 2% | 8 | $528,225 |
| 75247 | 2% | 0 | $0 |
| 75208 | 2% | 1 | $5,830 |
| 75224 | 2% | 5 | $57,595 |
| 75231 | 2% | 6 | $76,251 |
| 75249 | 2% | 0 | $0 |
| 75287 | 2% | 2 | $0 |
| 75252 | 2% | 14 | $189,443 |
| 75203 | 1% | 0 | $0 |
| 75206 | 1% | 14 | $704,811 |
| 75207 | 1% | 22 | $2.9 million |
| 75233 | 1% | 3 | $3,471 |
| 75240 | 1% | 22 | $292,038 |
| 75209 | 1% | 18 | $651,687 |
| 75223 | 1% | 0 | $0 |
| 75225 | 1% | 6 | $200,673 |
| 75204 | 1% | 5 | $272,199 |
| 75254 | 1% | 11 | $402,106 |
| 75210 | 1% | 0 | $0 |
| 75219 | 1% | 14 | $287,938 |
| 75244 | 1% | 9 | $499,659 |
| 75201 | under 1% | 0 | $0 |
| 75226 | under 1% | 4 | $70,533 |
| 75202 | under 1% | 0 | $0 |
| 75251 | under 1% | 0 | $0 |
| 75246 | under 1% | 6 | $212,633 |
| 75270 | 0% | 0 | $0 |
| 75390 | 0% | 0 | $0 |
Homes in Dallas
| Housing units | 590,237 |
| Median year built | 1981 |
| Built before 1980 | 48% |
| Built 2000 or later | 26% |
| Owner-occupied | 42% |
| Median value, owner-occupied | $320,700 |
| Single-family detached | 41% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Highland Park | 3 mi | 35% | under 1% |
| University Park | 4 mi | 33% | 0% |
| Cockrell Hill | 8 mi | 5% | under 1% |
| Balch Springs | 10 mi | 45% | 34% |
| Mesquite | 11 mi | 74% | 3% |
| Hutchins | 11 mi | 55% | 1% |
| Garland | 11 mi | 59% | under 1% |
| Farmers Branch | 11 mi | 45% | 3% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status