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Washington County, Wisconsin

A shallow water table limits basements on 44% of Washington County's mapped land, a higher share than 62% of US counties. Shrink-swell clay limits houses without basements on 1%.

None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 18 flood losses here since 2016. 45% of homes were built before 1980, against 50% nationally; the median home dates from 1986.

Data as of October 13, 2026 · sources

1%

expansive clay: shrink-swell limits slab homes

44%

high water table: limits basements

0%

in drought, October 13, 2026

45%

of homes built before 1980

Soil under Washington County

Expansive clay (limits slab homes)0.9%
High water table (limits basements)44.3%
Septic fields very limited81.0%
Clay swell (LEP, by area)3.4%
High-swell land (LEP 6%+)0.8%
Mapped soil278,765 acres
Soil seriesShare hereSeries nationally: high water table
Theresa12%n/a
Casco8%n/a
Houghton6%n/a
Ozaukee4%over 99%
Fox4%1%
Palms4%n/a
Ozaukee County: 43%Dodge County: 59%Waukesha County: 42%Fond du Lac County: 50%Sheboygan County: 37%Jefferson County: 57%Milwaukee County: 57%Green Lake County: 48%Washington County OzaukeeDodgeWaukeshaFond du LacSheboyganJeffersonMilwaukeeGreen LakeWashington
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 WI131 (2025-09-10)

What the numbers mean here

On 44% 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: 33.79 in, 0.22 in below the 1991-2020 average year of 34.01 in.

USDA rates 81% 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 9 of the last 52 weeks; the most was 100% of its area, on the July 28, 2026 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

18 flood losses since 2016, $360,077 paid. The worst year was 2025, with 8.

YearFlood losses
20160
20171
20183
20193
20200
20210
20220
20230
20240
20258
2026 to date3

Rain

Average year, 1991-202034.01 in
12 months to August 202633.79 in (-0.22)
202534.60 in (+0.59)
Wettest year since 18952018: 43.86 in
Driest year since 18951895: 21.29 in
Days with 1 inch or more, normal at HARTFORD WWTP (10 mi away)6.8

Homes

Housing units59,380
Median year built1986
Built before 198045%
Built 2000 or later28%
Owner-occupied78%
Median value, owner-occupied$344,800
Single-family detached69%

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
Ozaukee County, WI 21 mi 41% 43%
Dodge County, WI 24 mi 7% 59%
Waukesha County, WI 26 mi 3% 42%
Fond du Lac County, WI 28 mi 13% 50%
Sheboygan County, WI 35 mi 33% 37%
Jefferson County, WI 38 mi 4% 57%
Milwaukee County, WI 38 mi 8% 57%
Green Lake County, WI 46 mi 2% 48%

Sources: USDA SSURGO (September 10, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status