Marion County, Ohio
A shallow water table limits basements on 92% of Marion County's mapped land, a higher share than 97% of US counties. Shrink-swell clay limits houses without basements on 40%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 15 flood losses here since 2016. 74% of homes were built before 1980, against 50% nationally; the median home dates from 1963.
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) | 39.5% |
| High water table (limits basements) | 91.9% |
| Septic fields very limited | 94.6% |
| Clay swell (LEP, by area) | 5.0% |
| High-swell land (LEP 6%+) | 18.4% |
| Urban land, not rated | 2.0% |
| Mapped soil | 258,336 acres |
How we count · survey areas OH101 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 5.0% by land area here, and 18% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 40% of the mapped land.
On 92% 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: 39.38 in, 1.26 in above the 1991-2020 average year of 38.12 in.
USDA rates 95% 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 2 of the last 52 weeks; the most was 78.6% of its area, on the October 28, 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
15 flood losses since 2016, $56,357 paid. The worst year was 2019, with 6.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 6 |
| 2020 | 4 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 38.12 in |
| 12 months to August 2026 | 39.38 in (+1.26) |
| 2025 | 32.16 in (-5.96) |
| Wettest year since 1895 | 2011: 53.52 in |
| Driest year since 1895 | 1934: 21.29 in |
| Days with 1 inch or more, normal at MARION 2 N (3 mi away) | 7.9 |
Homes
| Housing units | 27,358 |
| Median year built | 1963 |
| Built before 1980 | 74% |
| Built 2000 or later | 11% |
| Owner-occupied | 68% |
| Median value, owner-occupied | $156,800 |
| Single-family detached | 76% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Marion County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Caledonia | 15% | 98% | 146 |
| Green Camp | 39% | 84% | 150 |
| La Rue | 1% | 39% | 323 |
| Marion | 21% | 60% | 14,304 |
| Morral | 46% | 94% | 204 |
| New Bloomington | 78% | 92% | 184 |
| Prospect | 16% | 72% | 489 |
| Waldo | 22% | 98% | 171 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Wyandot County, OH | 19 mi | 30% | 90% |
| Morrow County, OH | 20 mi | 9% | 87% |
| Crawford County, OH | 22 mi | 3% | 93% |
| Union County, OH | 23 mi | 25% | 97% |
| Delaware County, OH | 23 mi | 23% | 84% |
| Hardin County, OH | 26 mi | 35% | 97% |
| Logan County, OH | 34 mi | 26% | 81% |
| Richland County, OH | 35 mi | 3% | 66% |
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