Marion County, Missouri
A shallow water table limits basements on 69% of Marion County's mapped land, a higher share than 81% of US counties. Shrink-swell clay limits houses without basements on 53%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 20 flood losses here since 2016. 63% of homes were built before 1980, against 50% nationally; the median home dates from 1971.
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 Marion County
| Expansive clay (limits slab homes) | 52.8% |
| High water table (limits basements) | 69.0% |
| Septic fields very limited | 93.4% |
| Clay swell (LEP, by area) | 6.5% |
| High-swell land (LEP 6%+) | 50.6% |
| Mapped soil | 284,365 acres |
How we count · survey areas MO127 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 6.5% by land area here, and 51% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 53% of the mapped land.
On 69% of Marion 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: 38.01 in, 1.71 in below the 1991-2020 average year of 39.72 in.
USDA rates 93% 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 24 of the last 52 weeks; the most was 100% of its area, in 10 weeks, most recently on the March 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0.5% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
20 flood losses since 2016, $757,790 paid. The worst year was 2019, with 13.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 1 |
| 2018 | 4 |
| 2019 | 13 |
| 2020 | 2 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 39.72 in |
| 12 months to August 2026 | 38.01 in (-1.71) |
| 2025 | 29.00 in (-10.72) |
| Wettest year since 1895 | 1973: 57.59 in |
| Driest year since 1895 | 1988: 21.75 in |
| Days with 1 inch or more, normal at QUINCY DAM 21 (13 mi away) | 9.4 |
Homes
| Housing units | 12,917 |
| Median year built | 1971 |
| Built before 1980 | 63% |
| Built 2000 or later | 15% |
| Owner-occupied | 69% |
| Median value, owner-occupied | $162,000 |
| 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 |
|---|---|---|---|
| Ralls County, MO | 19 mi | 56% | 75% |
| Lewis County, MO | 20 mi | 63% | 81% |
| Shelby County, MO | 24 mi | 87% | 91% |
| Adams County, IL | 26 mi | 36% | 70% |
| Monroe County, MO | 29 mi | 84% | 85% |
| Knox County, MO | 35 mi | 81% | 85% |
| Pike County, MO | 41 mi | 45% | 69% |
| Pike County, IL | 42 mi | 9% | 56% |
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