Ada, Ohio
Inside Ada's city limits, a shallow water table limits basements on over 99% of mapped land, the 3rd-highest of 8 cities in Hardin County. Shrink-swell clay limits houses without basements on 43%, the highest of 8 cities in Hardin County.
That water-table share is close to Hardin County's 97%. FEMA's flood data list no flood losses since 2016 in ZIP code 45810 overlapping the city. Of its 1,776 homes, 66% were built before 1980; the median dates from 1973.
Data as of October 13, 2026 · sources · in Hardin County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Basement waterproofing in Ada
Basement waterproofing in Ada: a shallow water table limits basements on over 99% of Ada's mapped land, more than in 95% of Ohio cities.
About 1,000 of Ada's 1,776 homes are detached houses.
Soil under Ada city limits
| Expansive clay (limits slab homes) | 43.4% |
| High water table (limits basements) | 99.6% |
| Septic fields very limited | 99.6% |
| Clay swell (LEP, by area) | 5.0% |
| High-swell land (LEP 6%+) | 2.5% |
| Mapped soil | 1,368 acres |
What the numbers mean here
Clay swell averages a linear extensibility of 5.0% by land area here, and 3% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 43% of the mapped land.
On over 99% of Ada's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates over 99% of the land very limited for septic absorption fields.
Drought in Hardin County
0% of Hardin County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap Ada. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 45810 | 100% | 0 | $0 |
Homes in Ada
| Housing units | 1,776 |
| Median year built | 1973 |
| Built before 1980 | 66% |
| Built 2000 or later | 16% |
| Owner-occupied | 44% |
| Median value, owner-occupied | $160,500 |
| Single-family detached | 55% |
Nearby cities
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status