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Onalaska, Texas
Inside Onalaska's city limits, shrink-swell clay limits houses without basements on 15% of mapped land, the 3rd-highest of 5 cities in Polk County. A shallow water table limits basements on 46%, the 4th-highest of 5 cities in Polk County.
That clay share is below Polk County's 23%. FEMA's flood data list 19 flood losses since 2016 in ZIP code 77360 overlapping the city. Of its 1,765 homes, 16% were built before 1980; the median dates from 1993.
Data as of October 13, 2026 · sources · in Polk 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 Onalaska
Foundation repair in Onalaska: shrink-swell clay limits slab homes on 15% of Onalaska's mapped land.
About 700 of Onalaska's 1,765 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 Onalaska city limits
| Expansive clay (limits slab homes) | 14.5% |
| High water table (limits basements) | 45.8% |
| Septic fields very limited | 82.4% |
| Clay swell (LEP, by area) | 3.3% |
| High-swell land (LEP 6%+) | 14.5% |
| Mapped soil | 3,501 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Pinetucky | 30% | n/a |
| Leggett | 12% | n/a |
| Oakhurst | 8% | n/a |
| Colita | 7% | n/a |
| Woodville | 7% | n/a |
| Laska | 7% | n/a |
What the numbers mean here
On 46% of Onalaska's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 82% of the land very limited for septic absorption fields.
Drought in Polk County
2.1% of Polk 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 Onalaska. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 77360 | 100% | 19 | $833,832 |
Homes in Onalaska
| Housing units | 1,765 |
| Median year built | 1993 |
| Built before 1980 | 16% |
| Built 2000 or later | 30% |
| Owner-occupied | 78% |
| Median value, owner-occupied | $165,800 |
| Single-family detached | 42% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Point Blank | 8 mi | 63% | 67% |
| Livingston | 13 mi | 55% | 44% |
| Seven Oaks | 15 mi | 8% | 83% |
| Groveton | 16 mi | 0% | 87% |
| Coldspring | 16 mi | 2% | 5% |
| Riverside | 17 mi | 54% | 58% |
| Trinity | 17 mi | 16% | 83% |
| Goodrich | 18 mi | 71% | 54% |
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