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Benton County, Washington

USDA's soil survey flags shrink-swell clay on 0% of Benton County's mapped land and a shallow water table under basements on 1%, both below the national shares of 15% and 29%. 52.4% of the county is in drought on the October 13, 2026 Drought Monitor map.

FEMA's flood data list 15 flood losses here since 2016. 45% of homes were built before 1980, against 50% nationally; the median home dates from 1988.

Data as of October 13, 2026 · sources

0%

expansive clay: shrink-swell limits slab homes

1%

high water table: limits basements

52%

in drought, October 13, 2026

45%

of homes built before 1980

Soil under Benton County

Expansive clay (limits slab homes)0.0%
High water table (limits basements)1.0%
Septic fields very limited46.1%
Clay swell (LEP, by area)1.2%
High-swell land (LEP 6%+)0.0%
Mapped soil1,142,249 acres
Soil seriesShare hereSeries nationally: expansive clay
Ritzville18%n/a
Warden15%n/a
Shano6%n/a
Hezel5%n/a
Quincy4%n/a
Kiona3%n/a
Franklin County: 0%Walla Walla County: 0%Morrow County: 7%Umatilla County: 7%Yakima County: 2%Klickitat County: 2%Grant County: 0%Gilliam County: 3%Benton County FranklinWalla WallaMorrowUmatillaYakimaKlickitatGrantGilliamBenton
Benton 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 WA605 (2025-08-28), WA706 (2025-08-28)

What the numbers mean here

Rain over the 12 months to August 2026: 8.92 in, 0.42 in above the 1991-2020 average year of 8.50 in.

With shrink-swell clay on 0% and a shallow water table on 1% of the land, the soil survey points to neither problem across most of Benton County; conditions still vary lot by lot.

Drought

52.4% 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 6 weeks, most recently on the November 25, 2025 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 worse52.4%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

15 flood losses since 2016, $255,669 paid. The worst year was 2025, with 11.

YearFlood losses
20160
20172
20180
20191
20200
20210
20220
20230
20241
202511
2026 to date0

Rain

Average year, 1991-20208.50 in
12 months to August 20268.92 in (+0.42)
20259.16 in (+0.66)
Wettest year since 18951983: 13.14 in
Driest year since 18951967: 4.25 in
Days with 1 inch or more, normal at RICHLAND (13 mi away)0

Homes

Housing units83,101
Median year built1988
Built before 198045%
Built 2000 or later35%
Owner-occupied68%
Median value, owner-occupied$407,800
Single-family detached63%

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 36 mi 0% under 1%
Walla Walla County, WA 50 mi 0% 4%
Morrow County, OR 56 mi 7% 1%
Umatilla County, OR 58 mi 7% 3%
Yakima County, WA 60 mi 2% 8%
Klickitat County, WA 65 mi 2% 5%
Grant County, WA 68 mi 0% 2%
Gilliam County, OR 69 mi 3% under 1%

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