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Austin, Texas
Inside Austin's city limits, shrink-swell clay limits houses without basements on 40% of mapped land. A shallow water table limits basements on under 1%.
That clay share is close to Travis County's 39%. FEMA's flood data list 232 flood losses since 2016 in the 37 ZIP codes overlapping the city. Of its 483,071 homes, 28% were built before 1980; the median dates from 1994.
Data as of November 3, 2026 · sources · in Travis County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 37 overlapping ZIPs
of homes built before 1980
Foundation repair in Austin
Foundation repair in Austin: shrink-swell clay limits slab homes on 40% of Austin's mapped land.
Whether the city requires a permit depends on the job, and Angi (October 10, 2025) publishes a range of $3,822 to $9,809 a job.
About 209,700 of Austin's 483,071 homes are detached houses.
| City permit | Depends on the job. Austin exempts a foundation repair of 128 square feet or less from a building permit; foundation repair is one of the projects its Residential Express permit covers. (City of Austin, Development Services Department, read October 2, 2026) |
| Contractor registration | A registered general contractor must be linked to an express permit; a homeowner can register and act as the general contractor. (City of Austin, Development Services Department) |
| 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 | Austin allows foundation watering on the assigned watering day and hours, and says to aim sprinklers at the ground about 18 inches from the foundation. (City of Austin, Austin Water) |
| Prices | Angi, October 10, 2025 · cost guide ranges compared |
Soil under Austin city limits
| Expansive clay (limits slab homes) | 39.6% |
| High water table (limits basements) | 0.1% |
| Septic fields very limited | 81.3% |
| Clay swell (LEP, by area) | 7.0% |
| High-swell land (LEP 6%+) | 35.7% |
| Urban land, not rated | 9.7% |
| Mapped soil | 212,212 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Eckrant | 13% | 8% |
| Houston Black | 9% | 91% |
| Brackett | 7% | 0% |
| Austin | 6% | 93% |
| Speck | 6% | n/a |
| Heiden | 5% | 80% |
What the numbers mean here
Clay swell averages a linear extensibility of 7.0% 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 40% of the mapped land.
Clay shrinks as it dries: 100% of Travis County is in drought on the latest map, and 40% of Austin's mapped land has shrink-swell clay.
USDA rates 81% of the land very limited for septic absorption fields.
Austin covers 324.8 square miles of land and counts 483,071 housing units, about 1,487 per square mile.
43% of Austin's occupied homes are owner-occupied, and the median owner-occupied home is valued at $555,300; 43% of all homes in the city date from 2000 or later.
The largest soil series under Austin is Eckrant, on 13% of the mapped land, followed by Houston Black at 9%.
USDA's soil survey maps 212,212 acres inside Austin's city limits.
Drought in Travis County
100% of Travis 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 Austin. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78744 | 6% | 10 | $473,355 |
| 78724 | 5% | 5 | $135,648 |
| 78730 | 4% | 7 | $11,814 |
| 78735 | 4% | 1 | $11,790 |
| 78759 | 4% | 12 | $146,681 |
| 78745 | 4% | 10 | $103,179 |
| 78748 | 4% | 5 | $34,374 |
| 78750 | 4% | 7 | $270,672 |
| 78746 | 3% | 4 | $43,476 |
| 78753 | 3% | 7 | $34,185 |
| 78749 | 3% | 3 | $42,935 |
| 78717 | 3% | 0 | $0 |
| 78754 | 3% | 6 | $119,439 |
| 78726 | 3% | 3 | $22,600 |
| 78739 | 3% | 1 | $0 |
| 78758 | 3% | 22 | $1.0 million |
| 78704 | 3% | 12 | $68,910 |
| 78731 | 3% | 16 | $674,481 |
| 78727 | 2% | 11 | $358,182 |
| 78741 | 2% | 0 | $0 |
| 78719 | 2% | 20 | $762,159 |
| 78723 | 2% | 11 | $240,053 |
| 78729 | 2% | 3 | $72,430 |
| 78747 | 2% | 7 | $63,651 |
| 78703 | 2% | 12 | $124,259 |
| 78702 | 2% | 0 | $0 |
| 78757 | 2% | 14 | $179,728 |
| 78732 | 1% | 5 | $166,134 |
| 78721 | 1% | 5 | $22,607 |
| 78752 | 1% | 2 | $0 |
| 78728 | 1% | 1 | $0 |
| 78751 | 1% | 5 | $30,423 |
| 78705 | 1% | 1 | $13,414 |
| 78701 | 1% | 1 | $0 |
| 78756 | 1% | 3 | $146,486 |
| 78722 | under 1% | 0 | $0 |
| 78712 | under 1% | 0 | $0 |
Homes in Austin
| Housing units | 483,071 |
| Median year built | 1994 |
| Built before 1980 | 28% |
| Built 2000 or later | 43% |
| Owner-occupied | 43% |
| Median value, owner-occupied | $555,300 |
| Single-family detached | 43% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
| Work | Range | Source |
|---|---|---|
| Foundation repair, Austin | $3,822 to $9,809 | Angi, October 10, 2025 |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Rollingwood | 3 mi | 3% | 0% |
| West Lake Hills | 4 mi | 4% | 0% |
| Sunset Valley | 6 mi | 58% | 0% |
| San Leanna | 11 mi | 35% | 0% |
| Manor | 12 mi | 84% | 1% |
| Bee Cave | 12 mi | 16% | 0% |
| Volente | 14 mi | 1% | 0% |
| Pflugerville | 14 mi | 66% | under 1% |
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