Darke County, Ohio
A shallow water table limits basements on 96% of Darke County's mapped land, a higher share than 99% of US counties and the 6th highest of 88 Ohio counties. Shrink-swell clay limits houses without basements on 26%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 8 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 Darke County
| Expansive clay (limits slab homes) | 25.9% |
| High water table (limits basements) | 95.9% |
| Septic fields very limited | 98.9% |
| Clay swell (LEP, by area) | 4.6% |
| High-swell land (LEP 6%+) | 2.3% |
| Mapped soil | 383,808 acres |
How we count · survey areas OH037 (2025-08-27)
What the numbers mean here
Clay swell averages a linear extensibility of 4.6% by land area here, and 2% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 26% of the mapped land.
On 96% of Darke 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: 45.75 in, 5.20 in above the 1991-2020 average year of 40.55 in.
USDA rates 99% 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 23 of the last 52 weeks; the most was 81.6% of its area, on the October 21, 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
8 flood losses since 2016, $56,404 paid. The worst year was 2021, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 3 |
| 2018 | 1 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 3 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 40.55 in |
| 12 months to August 2026 | 45.75 in (+5.20) |
| 2025 | 37.81 in (-2.74) |
| Wettest year since 1895 | 1950: 53.71 in |
| Driest year since 1895 | 1934: 23.58 in |
| Days with 1 inch or more, normal at GREENVILLE WTP (2 mi away) | 8.8 |
Homes
| Housing units | 22,651 |
| Median year built | 1963 |
| Built before 1980 | 74% |
| Built 2000 or later | 9% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $173,200 |
| Single-family detached | 81% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Darke County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Ansonia | 25% | 93% | 515 |
| Arcanum | 34% | 100% | 1,151 |
| Castine | 20% | over 99% | 32 |
| Gettysburg | 2% | 94% | 200 |
| Gordon | 45% | 100% | 128 |
| Greenville | 9% | 92% | 6,393 |
| Hollansburg | 15% | 100% | 141 |
| New Madison | 3% | 61% | 356 |
| New Weston | 15% | 100% | 36 |
| North Star | 28% | 100% | 68 |
| Osgood | 34% | 100% | 120 |
| Palestine | 1% | 94% | 72 |
| Pitsburg | 12% | over 99% | 193 |
| Rossburg | 21% | over 99% | 118 |
| Union City | 18% | over 99% | 796 |
| Versailles | 18% | 89% | 1,249 |
| Wayne Lakes | under 1% | 14% | 340 |
| Yorkshire | 32% | 100% | 22 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Randolph County, IN | 20 mi | 25% | 94% |
| Miami County, OH | 21 mi | 18% | 81% |
| Shelby County, OH | 26 mi | 24% | 94% |
| Preble County, OH | 27 mi | 17% | 86% |
| Wayne County, IN | 27 mi | 10% | 72% |
| Mercer County, OH | 28 mi | 37% | 95% |
| Jay County, IN | 29 mi | 60% | 96% |
| Montgomery County, OH | 31 mi | 17% | 65% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status