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Marion, Ohio
Inside Marion's city limits, a shallow water table limits basements on 60% of mapped land. Shrink-swell clay limits houses without basements on 21%, the 5th-highest of 8 cities in Marion County.
That water-table share is below Marion County's 92%. USDA doesn't rate the 32% of mapped land classed as urban land, so these shares are floors. FEMA's flood data list 3 flood losses since 2016 in ZIP code 43302 overlapping the city. Of its 14,304 homes, 84% were built before 1980; the median dates from 1954.
Data as of October 13, 2026 · sources · in Marion County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Basement waterproofing in Marion
Basement waterproofing in Marion: a shallow water table limits basements on 60% of Marion's mapped land, and the ZIP code overlapping Marion logged 3 FEMA flood losses since 2016.
About 10,300 of Marion's 14,304 homes are detached houses.
Soil under Marion city limits
| Expansive clay (limits slab homes) | 20.6% |
| High water table (limits basements) | 60.3% |
| Septic fields very limited | 62.0% |
| Clay swell (LEP, by area) | 5.0% |
| High-swell land (LEP 6%+) | 3.0% |
| Urban land, not rated | 31.6% |
| Mapped soil | 8,351 acres |
What the numbers mean here
Clay swell averages a linear extensibility of 5.0% by land area here, and 3% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 21% of the mapped land.
On 60% of Marion's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 62% of the land very limited for septic absorption fields.
Drought in Marion County
0% of Marion County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap Marion. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 43302 | 100% | 3 | $11,261 |
Homes in Marion
| Housing units | 14,304 |
| Median year built | 1954 |
| Built before 1980 | 84% |
| Built 2000 or later | 6% |
| Owner-occupied | 57% |
| Median value, owner-occupied | $119,500 |
| Single-family detached | 72% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Green Camp | 6 mi | 39% | 84% |
| Morral | 8 mi | 46% | 94% |
| Caledonia | 9 mi | 15% | 98% |
| Waldo | 10 mi | 22% | 98% |
| New Bloomington | 10 mi | 78% | 92% |
| Prospect | 10 mi | 16% | 72% |
| Harpster | 12 mi | 61% | 95% |
| La Rue | 14 mi | 1% | 39% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status