Boone County, Missouri
A shallow water table limits basements on 78% of Boone County's mapped land, a higher share than 87% of US counties. Shrink-swell clay limits houses without basements on 71%.
1.2% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 21 flood losses here since 2016. 34% of homes were built before 1980, against 50% nationally; the median home dates from 1991.
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 Boone County
| Expansive clay (limits slab homes) | 71.4% |
| High water table (limits basements) | 77.9% |
| Septic fields very limited | 96.0% |
| Clay swell (LEP, by area) | 7.3% |
| High-swell land (LEP 6%+) | 69.7% |
| Urban land, not rated | 1.5% |
| Mapped soil | 442,259 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Keswick | 20% | n/a |
| Mexico | 9% | n/a |
| Leonard | 8% | n/a |
| Weller | 7% | n/a |
| Menfro | 6% | 0% |
| Winfield | 4% | n/a |
How we count · survey areas MO019 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 7.3% by land area here, and 70% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 71% of the mapped land.
Clay shrinks as it dries: 1.2% of the county is in drought on the latest map, and 71% of Boone County's mapped land has shrink-swell clay.
On 78% of Boone 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: 46.88 in, 4.79 in above the 1991-2020 average year of 42.09 in.
USDA rates 96% of the land very limited for septic absorption fields.
Drought
1.2% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 19 of the last 52 weeks; the most was 100% of its area, in 6 weeks, most recently on the February 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 95.9% |
| D1 moderate drought or worse | 1.2% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
21 flood losses since 2016, $877,151 paid. The worst year was 2021, with 7.
| Year | Flood losses |
|---|---|
| 2016 | 5 |
| 2017 | 3 |
| 2018 | 0 |
| 2019 | 4 |
| 2020 | 0 |
| 2021 | 7 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 42.09 in |
| 12 months to August 2026 | 46.88 in (+4.79) |
| 2025 | 33.35 in (-8.74) |
| Wettest year since 1895 | 2008: 60.19 in |
| Driest year since 1895 | 1901: 22.49 in |
| Days with 1 inch or more, normal at COLUMBIA RGNL AP (13 mi away) | 11.8 |
Homes
| Housing units | 81,675 |
| Median year built | 1991 |
| Built before 1980 | 34% |
| Built 2000 or later | 36% |
| Owner-occupied | 58% |
| Median value, owner-occupied | $272,800 |
| Single-family detached | 61% |
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 |
|---|---|---|---|
| Howard County, MO | 23 mi | 35% | 59% |
| Callaway County, MO | 23 mi | 54% | 63% |
| Cooper County, MO | 29 mi | 37% | 66% |
| Moniteau County, MO | 29 mi | 23% | 80% |
| Audrain County, MO | 29 mi | 90% | 98% |
| Randolph County, MO | 33 mi | 83% | 85% |
| Cole County, MO | 34 mi | 14% | 69% |
| Monroe County, MO | 39 mi | 84% | 85% |
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