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Portsmouth, Ohio
Inside Portsmouth's city limits, a shallow water table limits basements on 16% of mapped land, the 4th-highest of 5 cities in Scioto County. Shrink-swell clay limits houses without basements on 3%, the 2nd-highest of 5 cities in Scioto County.
That water-table share is below Scioto County's 34%. FEMA's flood data list 10 flood losses since 2016 in ZIP code 45662 overlapping the city. Of its 8,466 homes, 90% were built before 1980; the median dates from 1946.
Data as of October 13, 2026 · sources · in Scioto 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 Portsmouth
Basement waterproofing in Portsmouth: a shallow water table limits basements on 16% of Portsmouth's mapped land, and the ZIP code overlapping Portsmouth logged 10 FEMA flood losses since 2016.
About 5,900 of Portsmouth's 8,466 homes are detached houses.
Soil under Portsmouth city limits
| Expansive clay (limits slab homes) | 2.9% |
| High water table (limits basements) | 15.6% |
| Septic fields very limited | 66.0% |
| Clay swell (LEP, by area) | 2.4% |
| High-swell land (LEP 6%+) | 2.9% |
| Urban land, not rated | 12.7% |
| Mapped soil | 7,088 acres |
What the numbers mean here
On 16% of Portsmouth's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 66% of the land very limited for septic absorption fields.
Drought in Scioto County
0% of Scioto 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 Portsmouth. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 45662 | 100% | 10 | $115,068 |
Homes in Portsmouth
| Housing units | 8,466 |
| Median year built | 1946 |
| Built before 1980 | 90% |
| Built 2000 or later | 3% |
| Owner-occupied | 48% |
| Median value, owner-occupied | $103,300 |
| Single-family detached | 70% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| New Boston | 1 mi | 1% | 7% |
| South Webster | 12 mi | 6% | 67% |
| Otway | 15 mi | under 1% | 48% |
| Hanging Rock | 18 mi | 1% | 7% |
| Rarden | 20 mi | 1% | 79% |
| Beaver | 21 mi | 2% | 81% |
| Ironton | 21 mi | 2% | 3% |
| Piketon | 22 mi | 18% | 50% |
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