Comal County, Texas
Shrink-swell clay limits houses without basements on 19% of Comal County's mapped land, a higher share than 68% of US counties. A shallow water table limits basements on under 1%.
82.6% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 50 flood losses here since 2016, 0% of them in buildings with basements. 17% of homes were built before 1980, against 50% nationally; the median home dates from 2005.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Comal County
| Expansive clay (limits slab homes) | 18.9% |
| High water table (limits basements) | 0.1% |
| Septic fields very limited | 82.7% |
| Clay swell (LEP, by area) | 5.4% |
| High-swell land (LEP 6%+) | 19.2% |
| Mapped soil | 434,214 acres |
How we count · survey areas TX604 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 5.4% by land area here, and 19% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 19% of the mapped land.
Clay shrinks as it dries: 82.6% of the county is in drought on the latest map, and 19% of Comal County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 29.93 in, 4.50 in below the 1991-2020 average year of 34.43 in.
USDA rates 83% of the land very limited for septic absorption fields.
Drought
82.6% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 43 of the last 52 weeks; the most was 100% of its area, in 34 weeks, most recently on the September 29, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 82.6% |
| D2 severe or worse | 18.5% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
50 flood losses since 2016, $688,054 paid. The worst year was 2016, with 14. Foundations of the buildings, where recorded: 85% slabs, 15% elevated.
| Year | Flood losses |
|---|---|
| 2016 | 14 |
| 2017 | 5 |
| 2018 | 2 |
| 2019 | 0 |
| 2020 | 9 |
| 2021 | 9 |
| 2022 | 0 |
| 2023 | 2 |
| 2024 | 0 |
| 2025 | 4 |
| 2026 to date | 5 |
Rain
| Average year, 1991-2020 | 34.43 in |
| 12 months to August 2026 | 29.93 in (-4.50) |
| 2025 | 26.85 in (-7.58) |
| Wettest year since 1895 | 1919: 55.11 in |
| Driest year since 1895 | 1954: 13.19 in |
| Days with 1 inch or more, normal at CANYON DAM (5 mi away) | 11.7 |
Homes
| Housing units | 77,961 |
| Median year built | 2005 |
| Built before 1980 | 17% |
| Built 2000 or later | 60% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $427,200 |
| Single-family detached | 75% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Comal County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Bulverde | 13% | 0% | 2,546 |
| Fair Oaks Ranch | 46% | under 1% | 3,991 |
| Garden Ridge | 21% | under 1% | 1,537 |
| New Braunfels | 59% | under 1% | 44,517 |
| Spring Branch | 18% | 0% | 100 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Hays County, TX | 22 mi | 14% | under 1% |
| Guadalupe County, TX | 24 mi | 52% | 8% |
| Kendall County, TX | 29 mi | 23% | 0% |
| Bexar County, TX | 30 mi | 51% | under 1% |
| Blanco County, TX | 32 mi | 28% | 0% |
| Caldwell County, TX | 38 mi | 59% | 6% |
| Travis County, TX | 45 mi | 39% | under 1% |
| Wilson County, TX | 45 mi | 36% | 2% |
Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status