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Karnes City, Texas
Inside Karnes City's city limits, shrink-swell clay limits houses without basements on 46% of mapped land, the 2nd-highest of 4 cities in Karnes County. A shallow water table limits basements on under 1%.
That clay share is below Karnes County's 52%. FEMA's flood data list no flood losses since 2016 in ZIP code 78118 overlapping the city. Of its 1,405 homes, 58% were built before 1980; the median dates from 1974.
Data as of October 13, 2026 · sources · in Karnes 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 Karnes City
Foundation repair in Karnes City: shrink-swell clay limits slab homes on 46% of Karnes City's mapped land, more than in 54% of Texas cities.
About 900 of Karnes City's 1,405 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 Karnes City city limits
| Expansive clay (limits slab homes) | 45.8% |
| High water table (limits basements) | 0.1% |
| Septic fields very limited | 49.0% |
| Clay swell (LEP, by area) | 6.1% |
| High-swell land (LEP 6%+) | 45.8% |
| Mapped soil | 1,503 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Pernitas | 38% | n/a |
| Coy | 27% | n/a |
| Monteola | 13% | n/a |
| Schattel | 4% | n/a |
| Eloso | 4% | n/a |
| Pettus | 3% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 6.1% by land area here, and 46% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 46% of the mapped land.
Clay shrinks as it dries: 100% of Karnes County is in drought on the latest map, and 46% of Karnes City's mapped land has shrink-swell clay.
Drought in Karnes County
100% of Karnes 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 Karnes City. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 78118 | 100% | 0 | $0 |
Homes in Karnes City
| Housing units | 1,405 |
| Median year built | 1974 |
| Built before 1980 | 58% |
| Built 2000 or later | 30% |
| Owner-occupied | 71% |
| Median value, owner-occupied | $93,400 |
| Single-family detached | 61% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Kenedy | 6 mi | 51% | under 1% |
| Falls City | 10 mi | 35% | 0% |
| Runge | 11 mi | 32% | under 1% |
| Poth | 17 mi | 51% | 1% |
| Nordheim | 18 mi | 62% | under 1% |
| Floresville | 24 mi | 16% | under 1% |
| Stockdale | 25 mi | 8% | 0% |
| Yorktown | 25 mi | 24% | 7% |
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