Johnson County, Texas
Shrink-swell clay limits houses without basements on 51% of Johnson County's mapped land, a higher share than 91% of US counties. A shallow water table limits basements on 4%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 37 flood losses here since 2016, 0% of them in buildings with basements. 25% of homes were built before 1980, against 50% nationally; the median home dates from 1997.
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 Johnson County
| Expansive clay (limits slab homes) | 50.9% |
| High water table (limits basements) | 3.8% |
| Septic fields very limited | 80.3% |
| Clay swell (LEP, by area) | 7.4% |
| High-swell land (LEP 6%+) | 55.4% |
| Mapped soil | 469,626 acres |
How we count · survey areas TX251 (2025-09-04)
What the numbers mean here
Clay swell averages a linear extensibility of 7.4% 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 51% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 51% of Johnson County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 28.30 in, 8.96 in below the 1991-2020 average year of 37.26 in.
USDA rates 80% 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 27 of the last 52 weeks; the most was 100% of its area, in 9 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 | 4.4% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
37 flood losses since 2016, $704,135 paid. The worst year was 2022, with 6. Foundations of the buildings, where recorded: 81% slabs, 7% crawl spaces, 11% elevated.
| Year | Flood losses |
|---|---|
| 2016 | 5 |
| 2017 | 0 |
| 2018 | 6 |
| 2019 | 0 |
| 2020 | 1 |
| 2021 | 6 |
| 2022 | 6 |
| 2023 | 5 |
| 2024 | 5 |
| 2025 | 2 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 37.26 in |
| 12 months to August 2026 | 28.30 in (-8.96) |
| 2025 | 37.34 in (+0.08) |
| Wettest year since 1895 | 2015: 63.35 in |
| Driest year since 1895 | 1963: 18.93 in |
| Days with 1 inch or more, normal at CLEBURNE (5 mi away) | 11.6 |
Homes
| Housing units | 70,796 |
| Median year built | 1997 |
| Built before 1980 | 25% |
| Built 2000 or later | 45% |
| Owner-occupied | 75% |
| Median value, owner-occupied | $285,900 |
| Single-family detached | 70% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Johnson County
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Somervell County, TX | 26 mi | 13% | 4% |
| Hood County, TX | 27 mi | 18% | 9% |
| Tarrant County, TX | 27 mi | 41% | 4% |
| Hill County, TX | 31 mi | 53% | 2% |
| Ellis County, TX | 33 mi | 72% | 4% |
| Bosque County, TX | 37 mi | 29% | 1% |
| Parker County, TX | 38 mi | 21% | 5% |
| Dallas County, TX | 43 mi | 51% | 6% |
Sources: USDA SSURGO (September 4, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status