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Mount Calm, Texas
Inside Mount Calm's city limits, shrink-swell clay limits houses without basements on 84% of mapped land, the 5th-highest of 14 cities in Hill County. A shallow water table limits basements on 18%, the highest of 14 cities in Hill County.
That clay share is above Hill County's 53%. FEMA's flood data list no flood losses since 2016 in ZIP code 76673 overlapping the city. Of its 220 homes, 34% were built before 1980; the median dates from 1992.
Data as of October 13, 2026 · sources · in Hill 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 Mount Calm
Foundation repair in Mount Calm: shrink-swell clay limits slab homes on 84% of Mount Calm's mapped land, more than in 92% of Texas cities.
About 100 of Mount Calm's 220 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 Mount Calm city limits
| Expansive clay (limits slab homes) | 84.4% |
| High water table (limits basements) | 18.1% |
| Septic fields very limited | 84.8% |
| Clay swell (LEP, by area) | 8.4% |
| High-swell land (LEP 6%+) | 84.4% |
| Mapped soil | 537 acres |
What the numbers mean here
Clay swell averages a linear extensibility of 8.4% by land area here, and 84% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 84% of the mapped land.
Clay shrinks as it dries: 100% of Hill County is in drought on the latest map, and 84% of Mount Calm's mapped land has shrink-swell clay.
On 18% of Mount Calm's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 85% of the land very limited for septic absorption fields.
Drought in Hill County
100% of Hill 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 Mount Calm. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 76673 | 100% | 0 | $0 |
Homes in Mount Calm
| Housing units | 220 |
| Median year built | 1992 |
| Built before 1980 | 34% |
| Built 2000 or later | 21% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $111,700 |
| Single-family detached | 47% |
Nearby cities
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