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Clark County, Washington

A shallow water table limits basements on 22% of Clark County's mapped land. Shrink-swell clay limits houses without basements on 3%.

None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 9 flood losses here since 2016. 33% of homes were built before 1980, against 50% nationally; the median home dates from 1993.

Data as of October 13, 2026 · sources

3%

expansive clay: shrink-swell limits slab homes

22%

high water table: limits basements

0%

in drought, October 13, 2026

33%

of homes built before 1980

Soil under Clark County

Expansive clay (limits slab homes)3.0%
High water table (limits basements)21.5%
Septic fields very limited84.3%
Clay swell (LEP, by area)2.9%
High-swell land (LEP 6%+)3.0%
Mapped soil404,544 acres
Soil seriesShare hereSeries nationally: high water table
Cinebar22%n/a
Olympic15%n/a
Hesson11%n/a
Hillsboro10%n/a
Kinney6%n/a
Gee5%n/a
Multnomah County: 30%Cowlitz County: 10%Columbia County: 35%Skamania County: 5%Washington County: 42%Hood River County: 5%Clackamas County: 30%Yamhill County: 36%Clark County MultnomahCowlitzColumbiaSkamaniaWashingtonHood RiverClackamasYamhillClark
Clark 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 WA011 (2025-08-28)

What the numbers mean here

On 22% of Clark 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: 63.94 in, 3.01 in below the 1991-2020 average year of 66.95 in.

USDA rates 84% 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 8 of the last 52 weeks; the most was 100% of its area, in 7 weeks, most recently on the December 2, 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 worse0%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

9 flood losses since 2016, $26,009 paid. The worst year was 2024, with 2.

YearFlood losses
20161
20172
20180
20190
20201
20211
20221
20230
20242
20250
2026 to date1

Rain

Average year, 1991-202066.95 in
12 months to August 202663.94 in (-3.01)
202561.46 in (-5.49)
Wettest year since 18951996: 100.31 in
Driest year since 18951929: 42.44 in
Days with 1 inch or more, normal at BATTLE GROUND (2 mi away)7.7

Homes

Housing units204,375
Median year built1993
Built before 198033%
Built 2000 or later35%
Owner-occupied66%
Median value, owner-occupied$522,900
Single-family detached67%

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
Multnomah County, OR 16 mi 0% 30%
Cowlitz County, WA 31 mi 4% 10%
Columbia County, OR 31 mi 7% 35%
Skamania County, WA 31 mi 4% 5%
Washington County, OR 33 mi 7% 42%
Hood River County, OR 44 mi 0% 5%
Clackamas County, OR 44 mi 5% 30%
Yamhill County, OR 54 mi 31% 36%

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