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Washington County, Pennsylvania

A shallow water table limits basements on 51% of Washington County's mapped land, a higher share than 67% of US counties. Shrink-swell clay limits houses without basements on 7%.

None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 306 flood losses here since 2016, 44% of them in buildings with basements. 66% of homes were built before 1980, against 50% nationally; the median home dates from 1966.

Data as of October 13, 2026 · sources

7%

expansive clay: shrink-swell limits slab homes

51%

high water table: limits basements

0%

in drought, October 13, 2026

66%

of homes built before 1980

Soil under Washington County

Expansive clay (limits slab homes)7.2%
High water table (limits basements)51.0%
Septic fields very limited97.5%
Clay swell (LEP, by area)3.3%
High-swell land (LEP 6%+)2.5%
Mapped soil550,288 acres
Soil seriesShare hereSeries nationally: high water table
Dormont32%n/a
Culleoka30%n/a
Guernsey10%n/a
Lowell5%4%
Weikert4%under 1%
Fairpoint3%n/a
Brooke County: 9%Ohio County: 7%Allegheny County: 31%Greene County: 59%Hancock County: 11%Jefferson County: 11%Marshall County: 48%Beaver County: 35%Washington County BrookeOhioAlleghenyGreeneHancockJeffersonMarshallBeaverWashington
Washington County (heavy outline) and nearby counties, shaded by high water table share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas PA611 (2025-09-05)

What the numbers mean here

On 51% of Washington 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: 41.51 in, 0.61 in below the 1991-2020 average year of 42.12 in.

USDA rates 98% 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 4 of the last 52 weeks; the most was 100% of its area, on the October 21, 2025 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse0%
D1 moderate drought or worse0%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

306 flood losses since 2016, $11.9 million paid. The worst year was 2024, with 83. Foundations of the buildings, where recorded: 44% basements, 36% slabs, 4% crawl spaces, 17% elevated. Median water depth outside the building: 15 in.

YearFlood losses
20168
201766
201867
20193
20207
202144
20224
20230
202483
202518
2026 to date6

Rain

Average year, 1991-202042.12 in
12 months to August 202641.51 in (-0.61)
202535.93 in (-6.19)
Wettest year since 18952018: 62.79 in
Driest year since 18951930: 24.94 in
Days with 1 inch or more, normal at CHARLEROI LOCK 4 (19 mi away)7.9

Homes

Housing units97,923
Median year built1966
Built before 198066%
Built 2000 or later17%
Owner-occupied76%
Median value, owner-occupied$228,500
Single-family detached74%

What repairs cost

Published ranges from cost guides, not quotes. More sources, and where they disagree.

WorkRangeSource
Basement waterproofing, US $3,000 to $10,000 Fixr, February 6, 2026
Sump pump installation, US $800 to $2,000 Fixr, January 31, 2025
Crawl space encapsulation, US $2,000 to $8,000 Fixr, August 29, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Brooke County, WV 18 mi 1% 9%
Ohio County, WV 21 mi 1% 7%
Allegheny County, PA 23 mi 10% 31%
Greene County, PA 24 mi 6% 59%
Hancock County, WV 28 mi 1% 11%
Jefferson County, OH 30 mi 21% 11%
Marshall County, WV 33 mi 5% 48%
Beaver County, PA 34 mi 6% 35%

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