Dallas County, Missouri
A shallow water table limits basements on 66% of Dallas County's mapped land, a higher share than 79% of US counties. Shrink-swell clay limits houses without basements on 22%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 49% of homes were built before 1980, against 50% nationally; the median home dates from 1981.
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 Dallas County
| Expansive clay (limits slab homes) | 21.9% |
| High water table (limits basements) | 66.2% |
| Septic fields very limited | 92.7% |
| Clay swell (LEP, by area) | 4.9% |
| High-swell land (LEP 6%+) | 30.4% |
| Mapped soil | 347,328 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Viraton | 19% | n/a |
| Ocie | 13% | n/a |
| Gatewood | 9% | n/a |
| Wilderness | 9% | n/a |
| Goss | 7% | 0% |
| Racket | 4% | n/a |
How we count · survey areas MO059 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 4.9% by land area here, and 30% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 22% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 22% of Dallas County's mapped land has shrink-swell clay.
On 66% of Dallas 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: 41.60 in, 2.75 in below the 1991-2020 average year of 44.35 in.
USDA rates 93% 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 28 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 | 100% |
| D3 extreme or worse | 94% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $0 paid. The worst year was 2022, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 1 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 44.35 in |
| 12 months to August 2026 | 41.60 in (-2.75) |
| 2025 | 40.28 in (-4.07) |
| Wettest year since 1895 | 1927: 66.46 in |
| Driest year since 1895 | 1953: 25.60 in |
| Days with 1 inch or more, normal at BUFFALO 2N (4 mi away) | 12.6 |
Homes
| Housing units | 7,613 |
| Median year built | 1981 |
| Built before 1980 | 49% |
| Built 2000 or later | 26% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $190,300 |
| Single-family detached | 79% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Polk County, MO | 21 mi | 24% | 59% |
| Hickory County, MO | 24 mi | 51% | 26% |
| Laclede County, MO | 24 mi | 14% | 55% |
| Camden County, MO | 28 mi | 34% | 22% |
| Webster County, MO | 29 mi | 20% | 68% |
| Greene County, MO | 34 mi | 9% | 49% |
| Wright County, MO | 42 mi | 5% | 47% |
| Cedar County, MO | 45 mi | 11% | 49% |
Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status