Knox County, Ohio
A shallow water table limits basements on 65% of Knox County's mapped land, a higher share than 78% of US counties. Shrink-swell clay limits houses without basements on under 1%.
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. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1973.
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 Knox County
| Expansive clay (limits slab homes) | 0.2% |
| High water table (limits basements) | 64.6% |
| Septic fields very limited | 95.9% |
| Clay swell (LEP, by area) | 3.0% |
| High-swell land (LEP 6%+) | 0.2% |
| Mapped soil | 338,868 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Homewood | 11% | n/a |
| Loudonville | 10% | n/a |
| Centerburg | 9% | over 99% |
| Bennington | 7% | 99% |
| Titusville | 4% | n/a |
| Chili | 4% | 0% |
How we count · survey areas OH083 (2025-09-02)
What the numbers mean here
On 65% of Knox 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: 46.03 in, 4.40 in above the 1991-2020 average year of 41.63 in.
USDA rates 96% 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. No part of the county was in drought in the last 52 weeks.
| 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, $105,776 paid. The worst year was 2017, with 5.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 5 |
| 2018 | 3 |
| 2019 | 1 |
| 2020 | 2 |
| 2021 | 1 |
| 2022 | 3 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 41.63 in |
| 12 months to August 2026 | 46.03 in (+4.40) |
| 2025 | 39.87 in (-1.76) |
| Wettest year since 1895 | 1990: 54.98 in |
| Driest year since 1895 | 1963: 25.55 in |
| Days with 1 inch or more, normal at DANVILLE 2 W (7 mi away) | 8.7 |
Homes
| Housing units | 26,078 |
| Median year built | 1973 |
| Built before 1980 | 58% |
| Built 2000 or later | 20% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $239,400 |
| Single-family detached | 83% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Knox County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Brinkhaven | 0% | 11% | 77 |
| Centerburg | under 1% | 97% | 713 |
| Danville | under 1% | 84% | 339 |
| Fredericktown | 0% | 44% | 1,269 |
| Gambier | 0% | 29% | 319 |
| Martinsburg | 0% | 24% | 125 |
| Mount Vernon | under 1% | 53% | 7,806 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Morrow County, OH | 21 mi | 9% | 87% |
| Licking County, OH | 22 mi | 1% | 69% |
| Richland County, OH | 26 mi | 3% | 66% |
| Coshocton County, OH | 27 mi | 3% | 46% |
| Holmes County, OH | 28 mi | under 1% | 62% |
| Ashland County, OH | 31 mi | 1% | 63% |
| Delaware County, OH | 32 mi | 23% | 84% |
| Muskingum County, OH | 39 mi | 17% | 39% |
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