Harrison County, Texas
Shrink-swell clay limits houses without basements on 24% of Harrison County's mapped land, a higher share than 75% of US counties. A shallow water table limits basements on 53%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 116 flood losses here since 2016, 2% of them in buildings with basements. 45% of homes were built before 1980, against 50% nationally; the median home dates from 1984.
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 Harrison County
| Expansive clay (limits slab homes) | 24.2% |
| High water table (limits basements) | 53.4% |
| Septic fields very limited | 84.8% |
| Clay swell (LEP, by area) | 3.9% |
| High-swell land (LEP 6%+) | 24.9% |
| Mapped soil | 585,082 acres |
How we count · survey areas TX203 (2025-09-04)
What the numbers mean here
Clay swell averages a linear extensibility of 3.9% by land area here, and 25% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 24% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 24% of Harrison County's mapped land has shrink-swell clay.
On 53% of Harrison County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 35.50 in, 14.93 in below the 1991-2020 average year of 50.43 in.
USDA rates 85% 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 46 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 | 100% |
| D3 extreme or worse | 98.1% |
| D4 exceptional | 0% |
Flood losses since 2016
116 flood losses since 2016, $3.6 million paid. The worst year was 2016, with 92. Foundations of the buildings, where recorded: 2% basements, 37% slabs, 10% crawl spaces, 51% elevated. Median water depth outside the building: 23 in.
| Year | Flood losses |
|---|---|
| 2016 | 92 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 16 |
| 2020 | 0 |
| 2021 | 2 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 3 |
| 2025 | 0 |
| 2026 to date | 3 |
Rain
| Average year, 1991-2020 | 50.43 in |
| 12 months to August 2026 | 35.50 in (-14.93) |
| 2025 | 49.80 in (-0.63) |
| Wettest year since 1895 | 1905: 74.45 in |
| Driest year since 1895 | 1943: 29.53 in |
| Days with 1 inch or more, normal at MARSHALL (5 mi away) | 17.5 |
Homes
| Housing units | 29,756 |
| Median year built | 1984 |
| Built before 1980 | 45% |
| Built 2000 or later | 30% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $180,400 |
| Single-family detached | 72% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Harrison County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Hallsville | 26% | 71% | 1,836 |
| Marshall | 6% | 38% | 10,007 |
| Scottsville | 19% | 44% | 172 |
| Uncertain | 63% | 77% | 250 |
| Waskom | 69% | 71% | 838 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Marion County, TX | 17 mi | 4% | 38% |
| Gregg County, TX | 26 mi | 9% | 43% |
| Panola County, TX | 27 mi | 50% | 61% |
| Caddo Parish, LA | 29 mi | 31% | 50% |
| Upshur County, TX | 35 mi | 2% | 38% |
| Cass County, TX | 37 mi | 4% | 37% |
| Rusk County, TX | 38 mi | 15% | 28% |
| Bossier Parish, LA | 44 mi | 47% | 58% |
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