Clay County, Missouri
A shallow water table limits basements on 75% of Clay County's mapped land, a higher share than 85% of US counties. Shrink-swell clay limits houses without basements on 61%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 63 flood losses here since 2016, 38% of them in buildings with basements. 42% of homes were built before 1980, against 50% nationally; the median home dates from 1987.
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 Clay County
| Expansive clay (limits slab homes) | 61.0% |
| High water table (limits basements) | 75.2% |
| Septic fields very limited | 88.5% |
| Clay swell (LEP, by area) | 6.5% |
| High-swell land (LEP 6%+) | 63.5% |
| Urban land, not rated | 4.6% |
| Mapped soil | 261,491 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Sharpsburg | 22% | 93% |
| Knox | 9% | n/a |
| Armster | 8% | n/a |
| Lagonda | 7% | n/a |
| Macksburg | 6% | n/a |
| Nodaway | 6% | n/a |
How we count · survey areas MO047 (2025-09-03)
What the numbers mean here
Clay swell averages a linear extensibility of 6.5% by land area here, and 63% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 61% of the mapped land.
On 75% of Clay 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: 39.73 in, 0.29 in above the 1991-2020 average year of 39.44 in.
USDA rates 88% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 12 of the last 52 weeks; the most was 100% of its area, in 5 weeks, most recently on the November 18, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
63 flood losses since 2016, $1.9 million paid. The worst year was 2017, with 26. Foundations of the buildings, where recorded: 38% basements, 35% slabs, 26% elevated. Median water depth outside the building: 17.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 9 |
| 2017 | 26 |
| 2018 | 0 |
| 2019 | 4 |
| 2020 | 3 |
| 2021 | 5 |
| 2022 | 1 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 1 |
| 2026 to date | 14 |
Rain
| Average year, 1991-2020 | 39.44 in |
| 12 months to August 2026 | 39.73 in (+0.29) |
| 2025 | 29.70 in (-9.74) |
| Wettest year since 1895 | 1973: 57.44 in |
| Driest year since 1895 | 1953: 22.05 in |
| Days with 1 inch or more, normal at KANSAS CITY DOWNTOWN AP (16 mi away) | 10.7 |
Homes
| Housing units | 107,719 |
| Median year built | 1987 |
| Built before 1980 | 42% |
| Built 2000 or later | 33% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $275,600 |
| Single-family detached | 71% |
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 |
|---|---|---|---|
| Platte County, MO | 19 mi | 30% | 57% |
| Clinton County, MO | 20 mi | 78% | 77% |
| Jackson County, MO | 22 mi | 36% | 50% |
| Ray County, MO | 23 mi | 71% | 84% |
| Wyandotte County, KS | 23 mi | 61% | 28% |
| Buchanan County, MO | 32 mi | 28% | 40% |
| Caldwell County, MO | 33 mi | 79% | 96% |
| Leavenworth County, KS | 34 mi | 63% | 52% |
Sources: USDA SSURGO (September 3, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status