Allen County, Ohio
A shallow water table limits basements on 93% of Allen County's mapped land, a higher share than 97% of US counties. Shrink-swell clay limits houses without basements on 31%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 51 flood losses here since 2016, 14% of them in buildings with basements. 73% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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 Allen County
| Expansive clay (limits slab homes) | 30.7% |
| High water table (limits basements) | 92.8% |
| Septic fields very limited | 94.7% |
| Clay swell (LEP, by area) | 4.6% |
| High-swell land (LEP 6%+) | 2.2% |
| Urban land, not rated | 2.3% |
| Mapped soil | 260,340 acres |
How we count · survey areas OH003 (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 31% of the mapped land.
On 93% of Allen 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: 38.75 in, 0.14 in below the 1991-2020 average year of 38.89 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 24 of the last 52 weeks; the most was 100% of its area, in 3 weeks, most recently on the November 4, 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
51 flood losses since 2016, $606,183 paid. The worst year was 2019, with 27. Foundations of the buildings, where recorded: 14% basements, 68% slabs, 19% crawl spaces. Median water depth outside the building: 4.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 3 |
| 2017 | 11 |
| 2018 | 3 |
| 2019 | 27 |
| 2020 | 2 |
| 2021 | 1 |
| 2022 | 2 |
| 2023 | 2 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 38.89 in |
| 12 months to August 2026 | 38.75 in (-0.14) |
| 2025 | 31.09 in (-7.80) |
| Wettest year since 1895 | 2011: 52.56 in |
| Driest year since 1895 | 1963: 22.70 in |
| Days with 1 inch or more, normal at LIMA WWTP (3 mi away) | 8.8 |
Homes
| Housing units | 44,791 |
| Median year built | 1966 |
| Built before 1980 | 73% |
| Built 2000 or later | 11% |
| Owner-occupied | 68% |
| Median value, owner-occupied | $165,300 |
| Single-family detached | 77% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Allen County
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Auglaize County, OH | 16 mi | 29% | 94% |
| Putnam County, OH | 18 mi | 66% | 96% |
| Hardin County, OH | 24 mi | 35% | 97% |
| Van Wert County, OH | 26 mi | 64% | 99% |
| Hancock County, OH | 28 mi | 33% | 93% |
| Shelby County, OH | 31 mi | 24% | 94% |
| Logan County, OH | 32 mi | 26% | 81% |
| Mercer County, OH | 32 mi | 37% | 95% |
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