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Adams County, Washington

USDA's soil survey flags shrink-swell clay on under 1% of Adams County's mapped land and a shallow water table under basements on 2%, both below the national shares of 15% and 29%. 100% of the county is in drought on the October 13, 2026 Drought Monitor map.

FEMA's flood data list 5 flood losses here since 2016. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1977.

Data as of October 13, 2026 · sources

<1%

expansive clay: shrink-swell limits slab homes

2%

high water table: limits basements

100%

in drought, October 13, 2026

58%

of homes built before 1980

Soil under Adams County

Expansive clay (limits slab homes)under 0.1%
High water table (limits basements)1.6%
Septic fields very limited58.8%
Clay swell (LEP, by area)1.5%
High-swell land (LEP 6%+)under 0.1%
Mapped soil1,234,800 acres
Soil seriesShare hereSeries nationally: expansive clay
Shano29%n/a
Ritzville25%n/a
Benge6%n/a
Walla Walla5%n/a
Anders3%n/a
Burke3%n/a
Franklin County: 0%Lincoln County: 1%Whitman County: 1%Grant County: 0%Walla Walla County: 0%Columbia County: 0%Garfield County: 13%Spokane County: 3%Adams County FranklinLincolnWhitmanGrantWalla WallaColumbiaGarfieldSpokaneAdams
Adams County (heavy outline) and nearby counties, shaded by expansive clay share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas WA001 (2025-08-28)

What the numbers mean here

Rain over the 12 months to August 2026: 10.55 in, 0.95 in below the 1991-2020 average year of 11.50 in.

USDA rates 59% of the land very limited for septic absorption fields.

With shrink-swell clay on under 1% and a shallow water table on 2% of the land, the soil survey points to neither problem across most of Adams County; conditions still vary lot by lot.

Drought

100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 20 weeks, most recently on the October 13, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse100%
D1 moderate drought or worse100%
D2 severe or worse18.2%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

5 flood losses since 2016, $2,435 paid. The worst year was 2025, with 2.

YearFlood losses
20160
20170
20180
20190
20200
20210
20220
20232
20241
20252
2026 to date0

Rain

Average year, 1991-202011.50 in
12 months to August 202610.55 in (-0.95)
202511.38 in (-0.12)
Wettest year since 18951948: 17.89 in
Driest year since 18951929: 5.50 in
Days with 1 inch or more, normal at LIND 3 NE (4 mi away)0

Homes

Housing units6,926
Median year built1977
Built before 198058%
Built 2000 or later22%
Owner-occupied69%
Median value, owner-occupied$273,300
Single-family detached61%

What repairs cost

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

WorkRangeSource
Foundation repair, US $2,200 to $8,200 Fixr, January 27, 2026
Pier-and-beam repair, US $2,000 to $15,000 Fixr, January 27, 2026
Foundation inspection, US $300 to $600 Fixr, January 31, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Franklin County, WA 39 mi 0% under 1%
Lincoln County, WA 39 mi 1% 4%
Whitman County, WA 46 mi 1% 15%
Grant County, WA 48 mi 0% 2%
Walla Walla County, WA 53 mi 0% 4%
Columbia County, WA 57 mi under 1% 4%
Garfield County, WA 61 mi 13% 2%
Spokane County, WA 66 mi 3% 16%

Sources: USDA SSURGO (August 28, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status