Franklin County, Ohio
A shallow water table limits basements on 71% of Franklin County's mapped land, a higher share than 82% of US counties. Shrink-swell clay limits houses without basements on 12%.
None of the county is in drought on the November 3, 2026 Drought Monitor map. FEMA's flood data list 315 flood losses here since 2016, 81% of them in buildings with basements. 52% of homes were built before 1980, against 50% nationally; the median home dates from 1979.
Data as of November 3, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, November 3, 2026
of homes built before 1980
Soil under Franklin County
| Expansive clay (limits slab homes) | 12.0% |
| High water table (limits basements) | 70.9% |
| Septic fields very limited | 80.6% |
| Clay swell (LEP, by area) | 4.2% |
| High-swell land (LEP 6%+) | 1.0% |
| Urban land, not rated | 10.8% |
| Mapped soil | 348,160 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Crosby | 21% | 99% |
| Bennington | 12% | 99% |
| Kokomo | 12% | 98% |
| Celina | 6% | 94% |
| Miamian | 4% | 78% |
| Cardington | 4% | 99% |
How we count · survey areas OH049 (2025-08-27)
What the numbers mean here
On 71% of Franklin 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: 47.38 in, 6.26 in above the 1991-2020 average year of 41.12 in.
USDA rates 81% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the November 3, 2026 map. No part of the county was in drought in the last 52 weeks.
| Category, November 3, 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
315 flood losses since 2016, $3.1 million paid. The worst year was 2020, with 131. Foundations of the buildings, where recorded: 81% basements, 7% slabs, 9% crawl spaces, 4% elevated. Median water depth outside the building: 10.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 17 |
| 2017 | 17 |
| 2018 | 9 |
| 2019 | 7 |
| 2020 | 131 |
| 2021 | 17 |
| 2022 | 36 |
| 2023 | 7 |
| 2024 | 3 |
| 2025 | 1 |
| 2026 to date | 70 |
Rain
| Average year, 1991-2020 | 41.12 in |
| 12 months to August 2026 | 47.38 in (+6.26) |
| 2025 | 39.43 in (-1.69) |
| Wettest year since 1895 | 2018: 55.12 in |
| Driest year since 1895 | 1934: 25.68 in |
| Days with 1 inch or more, normal at COLUMBUS PORT COLUMBUS INTL AP (7 mi away) | 8.4 |
Homes
| Housing units | 595,469 |
| Median year built | 1979 |
| Built before 1980 | 52% |
| Built 2000 or later | 23% |
| Owner-occupied | 53% |
| Median value, owner-occupied | $288,400 |
| Single-family detached | 52% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Franklin County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Bexley | under 1% | 65% | 4,805 |
| Brice | 5% | 98% | 82 |
| Canal Winchester | 16% | 85% | 3,996 |
| Columbus | 8% | 63% | 425,182 |
| Dublin | 26% | 79% | 18,639 |
| Gahanna | 2% | 71% | 14,673 |
| Grandview Heights | 1% | 22% | 4,238 |
| Grove City | 17% | 83% | 18,486 |
| Groveport | 12% | 65% | 2,334 |
| Harrisburg | 0% | 11% | 149 |
| Hilliard | 31% | 88% | 14,931 |
| Lockbourne | under 1% | 35% | 68 |
| Marble Cliff | 0% | 20% | 441 |
| Minerva Park | 0% | 60% | 781 |
| New Albany | 1% | 99% | 3,851 |
| Obetz | 10% | 67% | 2,600 |
| Reynoldsburg | 1% | 82% | 17,986 |
| Riverlea | 0% | 35% | 218 |
| Upper Arlington | 2% | 47% | 14,936 |
| Urbancrest | 10% | 63% | 414 |
| Valleyview | 0% | 24% | 292 |
| Westerville | 5% | 63% | 15,912 |
| Whitehall | under 1% | 63% | 8,900 |
| Worthington | under 1% | 49% | 6,406 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Delaware County, OH | 21 mi | 23% | 84% |
| Madison County, OH | 21 mi | 36% | 94% |
| Pickaway County, OH | 22 mi | 19% | 72% |
| Fairfield County, OH | 25 mi | 5% | 60% |
| Licking County, OH | 29 mi | 1% | 69% |
| Union County, OH | 29 mi | 25% | 97% |
| Fayette County, OH | 37 mi | 37% | 96% |
| Morrow County, OH | 40 mi | 9% | 87% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status