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Delaware, Ohio
Inside Delaware's city limits, a shallow water table limits basements on 72% of mapped land, higher than 56% of Ohio cities. Shrink-swell clay limits houses without basements on 23%, the 2nd-highest of 7 cities in Delaware County.
That water-table share is below Delaware County's 84%. FEMA's flood data list 15 flood losses since 2016 in ZIP code 43015 overlapping the city. Of its 17,726 homes, 36% were built before 1980; the median dates from 1995.
Data as of November 3, 2026 · sources · in Delaware 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 Delaware
Basement waterproofing in Delaware: a shallow water table limits basements on 72% of Delaware's mapped land, more than in 56% of Ohio cities, and the ZIP code overlapping Delaware logged 15 FEMA flood losses since 2016.
About 11,200 of Delaware's 17,726 homes are detached houses.
Soil under Delaware city limits
| Expansive clay (limits slab homes) | 23.2% |
| High water table (limits basements) | 72.1% |
| Septic fields very limited | 77.3% |
| Clay swell (LEP, by area) | 4.8% |
| High-swell land (LEP 6%+) | 1.2% |
| Urban land, not rated | 7.8% |
| Mapped soil | 13,128 acres |
What the numbers mean here
Clay swell averages a linear extensibility of 4.8% by land area here, and 1% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 23% of the mapped land.
On 72% of Delaware's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 77% of the land very limited for septic absorption fields.
Delaware covers 20.4 square miles of land and counts 17,726 housing units, about 869 per square mile.
65% of Delaware's occupied homes are owner-occupied, and the median owner-occupied home is valued at $318,400; 41% of all homes in the city date from 2000 or later.
The largest soil series under Delaware is Blount, on 30% of the mapped land, followed by Pewamo at 22%.
USDA's soil survey maps 13,128 acres inside Delaware's city limits.
Drought in Delaware County
0% of Delaware County is in drought (D1 or worse) on the November 3, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap Delaware. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 43015 | 98% | 15 | $262,101 |
Homes in Delaware
| Housing units | 17,726 |
| Median year built | 1995 |
| Built before 1980 | 36% |
| Built 2000 or later | 41% |
| Owner-occupied | 65% |
| Median value, owner-occupied | $318,400 |
| Single-family detached | 63% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Ostrander | 7 mi | 4% | 86% |
| Powell | 8 mi | 12% | 71% |
| Shawnee Hills | 9 mi | 6% | 94% |
| Ashley | 11 mi | 28% | 98% |
| Magnetic Springs | 11 mi | 25% | 97% |
| Sunbury | 11 mi | 15% | 92% |
| Galena | 11 mi | 8% | 80% |
| Waldo | 12 mi | 22% | 98% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status