Montgomery County, Ohio
A shallow water table limits basements on 65% of Montgomery County's mapped land, a higher share than 78% of US counties. Shrink-swell clay limits houses without basements on 17%.
None of the county is in drought on the November 3, 2026 Drought Monitor map. FEMA's flood data list 67 flood losses here since 2016, 65% of them in buildings with basements. 74% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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 Montgomery County
| Expansive clay (limits slab homes) | 17.2% |
| High water table (limits basements) | 64.6% |
| Septic fields very limited | 88.8% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 5.9% |
| Urban land, not rated | 7.6% |
| Mapped soil | 297,152 acres |
How we count · survey areas OH113 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 4.5% by land area here, and 6% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 17% of the mapped land.
On 65% of Montgomery 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: 49.25 in, 7.62 in above the 1991-2020 average year of 41.63 in.
USDA rates 89% 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
67 flood losses since 2016, $674,979 paid. The worst year was 2026, with 22. Foundations of the buildings, where recorded: 65% basements, 19% slabs, 15% crawl spaces, 2% elevated. Median water depth outside the building: 11 in.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 8 |
| 2018 | 9 |
| 2019 | 4 |
| 2020 | 14 |
| 2021 | 3 |
| 2022 | 2 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 5 |
| 2026 to date | 22 |
Rain
| Average year, 1991-2020 | 41.63 in |
| 12 months to August 2026 | 49.25 in (+7.62) |
| 2025 | 41.16 in (-0.47) |
| Wettest year since 1895 | 2011: 57.86 in |
| Driest year since 1895 | 1934: 24.95 in |
| Days with 1 inch or more, normal at DAYTON MCD (5 mi away) | 9.4 |
Homes
| Housing units | 252,843 |
| Median year built | 1966 |
| Built before 1980 | 74% |
| Built 2000 or later | 10% |
| Owner-occupied | 63% |
| Median value, owner-occupied | $180,900 |
| Single-family detached | 67% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Montgomery County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Brookville | 30% | 96% | 2,714 |
| Centerville | 17% | 54% | 12,143 |
| Clayton | 15% | 84% | 5,581 |
| Dayton | 6% | 28% | 70,335 |
| Englewood | 24% | 66% | 5,838 |
| Farmersville | 18% | 95% | 390 |
| Germantown | 5% | 59% | 2,300 |
| Huber Heights | 14% | 67% | 18,487 |
| Kettering | 6% | 28% | 27,191 |
| Miamisburg | 12% | 57% | 7,937 |
| Moraine | 3% | 33% | 3,132 |
| New Lebanon | 31% | 95% | 1,479 |
| Oakwood | 3% | 16% | 3,696 |
| Phillipsburg | 28% | 100% | 264 |
| Riverside | 3% | 32% | 11,782 |
| Trotwood | 22% | 65% | 12,254 |
| Union | 18% | 50% | 3,035 |
| Vandalia | 11% | 73% | 6,819 |
| West Carrollton | 3% | 22% | 6,162 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Preble County, OH | 19 mi | 17% | 86% |
| Miami County, OH | 21 mi | 18% | 81% |
| Greene County, OH | 21 mi | 8% | 68% |
| Warren County, OH | 24 mi | 10% | 51% |
| Butler County, OH | 26 mi | 13% | 30% |
| Clark County, OH | 29 mi | 17% | 59% |
| Darke County, OH | 31 mi | 26% | 96% |
| Clinton County, OH | 35 mi | 16% | 93% |
Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status