Nez Perce County, Idaho
A shallow water table limits basements on 15% of Nez Perce County's mapped land and the 7th highest of 43 Idaho counties. Shrink-swell clay limits houses without basements on 7%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list no flood losses here since 2016. 62% 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 Nez Perce County
| Expansive clay (limits slab homes) | 6.9% |
| High water table (limits basements) | 15.0% |
| Septic fields very limited | 90.8% |
| Clay swell (LEP, by area) | 4.0% |
| High-swell land (LEP 6%+) | 10.2% |
| Mapped soil | 546,021 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Kettenbach | 9% | n/a |
| Klickson | 7% | n/a |
| Naff | 6% | n/a |
| Linville | 5% | n/a |
| Hooverton | 5% | n/a |
| Southwick | 4% | n/a |
How we count · survey areas ID611 (2025-08-27)
What the numbers mean here
On 15% of Nez Perce 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: 23.24 in, 1.19 in above the 1991-2020 average year of 22.05 in.
USDA rates 91% 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 | 100% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Nez Perce County since 2016.
Rain
| Average year, 1991-2020 | 22.05 in |
| 12 months to August 2026 | 23.24 in (+1.19) |
| 2025 | 19.76 in (-2.29) |
| Wettest year since 1895 | 1927: 30.84 in |
| Driest year since 1895 | 1935: 14.41 in |
| Days with 1 inch or more, normal at LEWISTON NEZ PERCE CO AP (12 mi away) | 0.2 |
Homes
| Housing units | 18,578 |
| Median year built | 1973 |
| Built before 1980 | 62% |
| Built 2000 or later | 16% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $334,700 |
| Single-family detached | 68% |
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 |
|---|---|---|---|
| Lewis County, ID | 17 mi | 23% | 33% |
| Asotin County, WA | 24 mi | 29% | 5% |
| Latah County, ID | 34 mi | 5% | 43% |
| Garfield County, WA | 38 mi | 13% | 2% |
| Columbia County, WA | 54 mi | under 1% | 4% |
| Whitman County, WA | 54 mi | 1% | 15% |
| Wallowa County, OR | 55 mi | 31% | 11% |
| Clearwater County, ID | 58 mi | 1% | 14% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status