Wallowa County, Oregon
Shrink-swell clay limits houses without basements on 31% of Wallowa County's mapped land, a higher share than 81% of US counties and the 4th highest of 35 Oregon counties. A shallow water table limits basements on 11%.
The soil survey maps 46% of the county's land area; these shares describe the mapped part. 100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 59% of homes were built before 1980, against 50% nationally; the median home dates from 1973.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Wallowa County
| Expansive clay (limits slab homes) | 30.8% |
| High water table (limits basements) | 11.1% |
| Septic fields very limited | 96.4% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 33.8% |
| Mapped soil | 931,197 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Harlow | 9% | n/a |
| Bocker | 8% | n/a |
| Anatone | 5% | n/a |
| Cowsly | 5% | n/a |
| Snell | 4% | n/a |
| Imnaha | 4% | n/a |
How we count · survey areas OR670 (2025-09-10)
What the numbers mean here
Clay swell averages a linear extensibility of 4.5% by land area here, and 34% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 31% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 31% of Wallowa County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 23.32 in, 3.50 in below the 1991-2020 average year of 26.82 in.
USDA rates 96% of the land very limited for septic absorption fields.
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 52 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 96% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $0 paid. The worst year was 2019, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 26.82 in |
| 12 months to August 2026 | 23.32 in (-3.50) |
| 2025 | 24.34 in (-2.48) |
| Wettest year since 1895 | 1913: 35.32 in |
| Driest year since 1895 | 1935: 17.18 in |
| Days with 1 inch or more, normal at WALLOWA (17 mi away) | 0.8 |
Homes
| Housing units | 4,349 |
| Median year built | 1973 |
| Built before 1980 | 59% |
| Built 2000 or later | 22% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $394,800 |
| Single-family detached | 81% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Asotin County, WA | 41 mi | 29% | 5% |
| Union County, OR | 44 mi | 26% | 21% |
| Nez Perce County, ID | 55 mi | 7% | 15% |
| Lewis County, ID | 58 mi | 23% | 33% |
| Columbia County, WA | 59 mi | under 1% | 4% |
| Garfield County, WA | 60 mi | 13% | 2% |
| Adams County, ID | 61 mi | 9% | 7% |
| Baker County, OR | 66 mi | 47% | 7% |
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