Washington County, Texas
Shrink-swell clay limits houses without basements on 54% of Washington County's mapped land, a higher share than 92% of US counties. A shallow water table limits basements on 9%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 43 flood losses here since 2016. 37% of homes were built before 1980, against 50% nationally; the median home dates from 1989.
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 Washington County
| Expansive clay (limits slab homes) | 54.3% |
| High water table (limits basements) | 9.0% |
| Septic fields very limited | 77.3% |
| Clay swell (LEP, by area) | 8.4% |
| High-swell land (LEP 6%+) | 54.9% |
| Mapped soil | 397,370 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Frelsburg | 12% | 93% |
| Carbengle | 8% | n/a |
| Bleiblerville | 6% | n/a |
| Falba | 5% | n/a |
| Trinity | 5% | n/a |
| Latium | 4% | n/a |
How we count · survey areas TX477 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 8.4% by land area here, and 55% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 54% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 54% of Washington County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 30.29 in, 13.40 in below the 1991-2020 average year of 43.69 in.
USDA rates 77% of the land very limited for septic absorption fields.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 44 of the last 52 weeks; the most was 100% of its area, in 31 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 49.4% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
43 flood losses since 2016, $1.5 million paid. The worst year was 2016, with 37.
| Year | Flood losses |
|---|---|
| 2016 | 37 |
| 2017 | 4 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 43.69 in |
| 12 months to August 2026 | 30.29 in (-13.40) |
| 2025 | 33.37 in (-10.32) |
| Wettest year since 1895 | 2015: 69.39 in |
| Driest year since 1895 | 1917: 17.89 in |
| Days with 1 inch or more, normal at BRENHAM (4 mi away) | 14.2 |
Homes
| Housing units | 17,642 |
| Median year built | 1989 |
| Built before 1980 | 37% |
| Built 2000 or later | 37% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $288,100 |
| Single-family detached | 73% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Washington County
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Burleson County, TX | 23 mi | 50% | 17% |
| Austin County, TX | 24 mi | 38% | 20% |
| Waller County, TX | 29 mi | 24% | 40% |
| Brazos County, TX | 31 mi | 57% | 26% |
| Grimes County, TX | 34 mi | 61% | 40% |
| Lee County, TX | 35 mi | 48% | 25% |
| Fayette County, TX | 38 mi | 67% | 14% |
| Colorado County, TX | 43 mi | 37% | 24% |
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