Warren County, Ohio
A shallow water table limits basements on 51% of Warren County's mapped land, a higher share than 67% of US counties. Shrink-swell clay limits houses without basements on 10%.
None of the county is in drought on the November 3, 2026 Drought Monitor map. FEMA's flood data list 44 flood losses here since 2016, 42% of them in buildings with basements. 31% of homes were built before 1980, against 50% nationally; the median home dates from 1995.
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 Warren County
| Expansive clay (limits slab homes) | 9.9% |
| High water table (limits basements) | 51.2% |
| Septic fields very limited | 86.8% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 11.7% |
| Urban land, not rated | 7.5% |
| Mapped soil | 260,864 acres |
How we count · survey areas OH165 (2025-09-08)
What the numbers mean here
On 51% of Warren 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: 50.39 in, 6.73 in above the 1991-2020 average year of 43.66 in.
USDA rates 87% 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
44 flood losses since 2016, $897,268 paid. The worst year was 2018, with 13. Foundations of the buildings, where recorded: 42% basements, 38% slabs, 13% crawl spaces, 8% elevated. Median water depth outside the building: 14 in.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 8 |
| 2018 | 13 |
| 2019 | 2 |
| 2020 | 4 |
| 2021 | 6 |
| 2022 | 5 |
| 2023 | 1 |
| 2024 | 2 |
| 2025 | 1 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 43.66 in |
| 12 months to August 2026 | 50.39 in (+6.73) |
| 2025 | 44.00 in (+0.34) |
| Wettest year since 1895 | 2011: 59.58 in |
| Driest year since 1895 | 1934: 25.25 in |
| Days with 1 inch or more, normal at KINGS MILLS (7 mi away) | 10.7 |
Homes
| Housing units | 96,061 |
| Median year built | 1995 |
| Built before 1980 | 31% |
| Built 2000 or later | 39% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $349,400 |
| Single-family detached | 77% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Warren County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Butlerville | 6% | 77% | 63 |
| Carlisle | under 1% | 13% | 2,397 |
| Corwin | under 1% | 19% | 298 |
| Franklin | 2% | 27% | 5,032 |
| Harveysburg | under 1% | 67% | 337 |
| Lebanon | 16% | 27% | 8,647 |
| Maineville | 3% | 77% | 697 |
| Mason | 4% | 41% | 13,866 |
| Morrow | 11% | 16% | 881 |
| Pleasant Plain | 2% | 100% | 67 |
| South Lebanon | 9% | 25% | 2,367 |
| Springboro | 8% | 28% | 7,185 |
| Waynesville | 4% | 20% | 1,113 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Clinton County, OH | 20 mi | 16% | 93% |
| Butler County, OH | 21 mi | 13% | 30% |
| Greene County, OH | 23 mi | 8% | 68% |
| Montgomery County, OH | 24 mi | 17% | 65% |
| Hamilton County, OH | 25 mi | 7% | 9% |
| Clermont County, OH | 26 mi | 8% | 67% |
| Preble County, OH | 33 mi | 17% | 86% |
| Highland County, OH | 35 mi | 3% | 66% |
Sources: USDA SSURGO (September 8, 2025) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status