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Dauphin County, Pennsylvania
A shallow water table limits basements on 21% of Dauphin County's mapped land. Shrink-swell clay limits houses without basements on under 1%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 218 flood losses here since 2016, 61% of them in buildings with basements. 62% of homes were built before 1980, against 50% nationally; the median home dates from 1972.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Dauphin County
| Expansive clay (limits slab homes) | 0.2% |
| High water table (limits basements) | 21.5% |
| Septic fields very limited | 82.3% |
| Clay swell (LEP, by area) | 1.7% |
| High-swell land (LEP 6%+) | 0.2% |
| Urban land, not rated | 2.5% |
| Mapped soil | 345,486 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Calvin | 12% | n/a |
| Laidig | 12% | n/a |
| Dekalb | 9% | n/a |
| Berks | 8% | under 1% |
| Lehew | 8% | n/a |
| Leck Kill | 6% | n/a |
How we count · survey areas PA043 (2025-09-05)
What the numbers mean here
On 21% of Dauphin 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: 36.73 in, 9.24 in below the 1991-2020 average year of 45.97 in.
USDA rates 82% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 35 of the last 52 weeks; the most was 100% of its area, in 8 weeks, most recently on the March 3, 2026 map.
| Category, October 13, 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
218 flood losses since 2016, $3.0 million paid. The worst year was 2018, with 116. Foundations of the buildings, where recorded: 61% basements, 13% slabs, 4% crawl spaces, 23% elevated. Median water depth outside the building: 18 in.
| Year | Flood losses |
|---|---|
| 2016 | 3 |
| 2017 | 43 |
| 2018 | 116 |
| 2019 | 5 |
| 2020 | 2 |
| 2021 | 37 |
| 2022 | 6 |
| 2023 | 0 |
| 2024 | 2 |
| 2025 | 1 |
| 2026 to date | 3 |
Rain
| Average year, 1991-2020 | 45.97 in |
| 12 months to August 2026 | 36.73 in (-9.24) |
| 2025 | 39.93 in (-6.04) |
| Wettest year since 1895 | 2011: 73.02 in |
| Driest year since 1895 | 1930: 27.21 in |
| Days with 1 inch or more, normal at MIDDLETOWN HARRISBURG INTL AP (15 mi away) | 10.8 |
Homes
| Housing units | 127,828 |
| Median year built | 1972 |
| Built before 1980 | 62% |
| Built 2000 or later | 17% |
| Owner-occupied | 63% |
| Median value, owner-occupied | $236,400 |
| Single-family detached | 50% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Lebanon County, PA | 18 mi | 1% | 30% |
| Perry County, PA | 25 mi | under 1% | 29% |
| Snyder County, PA | 28 mi | 1% | 28% |
| Cumberland County, PA | 30 mi | 1% | 23% |
| Northumberland County, PA | 31 mi | under 1% | 27% |
| Juniata County, PA | 33 mi | 1% | 33% |
| York County, PA | 34 mi | under 1% | 20% |
| Schuylkill County, PA | 37 mi | 0% | 30% |
Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status