Harrison County, Missouri
A shallow water table limits basements on 68% of Harrison County's mapped land, a higher share than 80% of US counties. Shrink-swell clay limits houses without basements on 66%.
None 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. 67% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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) | 66.5% |
| High water table (limits basements) | 68.2% |
| Septic fields very limited | 99.5% |
| Clay swell (LEP, by area) | 6.8% |
| High-swell land (LEP 6%+) | 59.6% |
| Mapped soil | 464,198 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Shelby | 17% | n/a |
| Gara | 12% | 5% |
| Grundy | 11% | n/a |
| Adair | 10% | n/a |
| Zook | 9% | n/a |
| Lagonda | 7% | n/a |
How we count · survey areas MO081 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 6.8% by land area here, and 60% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 66% of the mapped land.
On 68% 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: 36.58 in, 2.00 in below the 1991-2020 average year of 38.58 in.
USDA rates 99% 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 10 of the last 52 weeks; the most was 100% of its area, in 5 weeks, most recently on the March 31, 2026 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
1 flood losses since 2016, $48,195 paid. The worst year was 2019, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 38.58 in |
| 12 months to August 2026 | 36.58 in (-2.00) |
| 2025 | 32.69 in (-5.89) |
| Wettest year since 1895 | 1993: 58.53 in |
| Driest year since 1895 | 1988: 17.46 in |
| Days with 1 inch or more, normal at BETHANY (6 mi away) | 11.3 |
Homes
| Housing units | 4,008 |
| Median year built | 1966 |
| Built before 1980 | 67% |
| Built 2000 or later | 17% |
| Owner-occupied | 71% |
| Median value, owner-occupied | $109,500 |
| Single-family detached | 81% |
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 |
|---|---|---|---|
| Mercer County, MO | 23 mi | 79% | 62% |
| Gentry County, MO | 24 mi | 68% | 71% |
| Worth County, MO | 24 mi | 41% | 58% |
| Daviess County, MO | 26 mi | 79% | 87% |
| Grundy County, MO | 28 mi | 75% | 78% |
| Decatur County, IA | 29 mi | 66% | 76% |
| Ringgold County, IA | 30 mi | 76% | 77% |
| DeKalb County, MO | 38 mi | 78% | 83% |
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