Benton County, Missouri
Shrink-swell clay limits houses without basements on 41% of Benton County's mapped land, a higher share than 87% of US counties. A shallow water table limits basements on 28%.
52.2% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 2 flood losses here since 2016. 42% of homes were built before 1980, against 50% nationally; the median home dates from 1985.
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 Benton County
| Expansive clay (limits slab homes) | 41.3% |
| High water table (limits basements) | 27.7% |
| Septic fields very limited | 81.9% |
| Clay swell (LEP, by area) | 5.8% |
| High-swell land (LEP 6%+) | 41.2% |
| Mapped soil | 481,382 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Bardley | 20% | n/a |
| Goss | 14% | 1% |
| Poynor | 8% | n/a |
| Eldon | 6% | n/a |
| Barden | 5% | n/a |
| Hartwell | 5% | n/a |
How we count · survey areas MO015 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 5.8% by land area here, and 41% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 41% of the mapped land.
Clay shrinks as it dries: 52.2% of the county is in drought on the latest map, and 41% of Benton County's mapped land has shrink-swell clay.
On 28% of Benton 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: 44.81 in, 1.85 in above the 1991-2020 average year of 42.96 in.
USDA rates 82% of the land very limited for septic absorption fields.
Drought
52.2% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 13 of the last 52 weeks; the most was 100% of its area, on the February 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 99.7% |
| D1 moderate drought or worse | 52.2% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $1,288 paid. The worst year was 2022, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 1 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 1 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 42.96 in |
| 12 months to August 2026 | 44.81 in (+1.85) |
| 2025 | 36.65 in (-6.31) |
| Wettest year since 1895 | 1951: 59.50 in |
| Driest year since 1895 | 1953: 23.22 in |
| Days with 1 inch or more, normal at TRUMAN DAM & RSVR (7 mi away) | 12 |
Homes
| Housing units | 13,594 |
| Median year built | 1985 |
| Built before 1980 | 42% |
| Built 2000 or later | 27% |
| Owner-occupied | 84% |
| Median value, owner-occupied | $177,900 |
| Single-family detached | 74% |
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 |
|---|---|---|---|
| Morgan County, MO | 24 mi | 28% | 46% |
| Hickory County, MO | 25 mi | 51% | 26% |
| Henry County, MO | 28 mi | 34% | 60% |
| Pettis County, MO | 29 mi | 68% | 76% |
| St. Clair County, MO | 32 mi | 23% | 33% |
| Camden County, MO | 34 mi | 34% | 22% |
| Johnson County, MO | 42 mi | 41% | 79% |
| Moniteau County, MO | 44 mi | 23% | 80% |
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