Butte County, Idaho
USDA's soil survey flags shrink-swell clay on 1% of Butte County's mapped land and a shallow water table under basements on 2%, both below the national shares of 15% and 29%. The soil survey maps 66% of the county's land area; these shares describe the mapped part.
89.8% of the county is in drought on the October 13, 2026 Drought Monitor map, down from 94.7% a week earlier. FEMA's flood data list no flood losses here since 2016. 72% of homes were built before 1980, against 50% nationally; the median home dates from 1971.
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 Butte County
| Expansive clay (limits slab homes) | 1.0% |
| High water table (limits basements) | 2.0% |
| Septic fields very limited | 60.4% |
| Clay swell (LEP, by area) | 2.3% |
| High-swell land (LEP 6%+) | 1.0% |
| Mapped soil | 948,933 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Simeroi | 6% | n/a |
| Nargon | 6% | n/a |
| McCarey | 4% | n/a |
| Atom | 3% | n/a |
| Zer | 3% | n/a |
| Ike | 3% | n/a |
How we count · survey areas ID758 (2025-08-27), ID761 (2025-08-27), ID763 (2025-08-27), ID780 (2025-08-27)
What the numbers mean here
Rain over the 12 months to August 2026: 11.66 in, 1.12 in below the 1991-2020 average year of 12.78 in.
USDA rates 60% of the land very limited for septic absorption fields.
With shrink-swell clay on 1% and a shallow water table on 2% of the land, the soil survey points to neither problem across most of Butte County; conditions still vary lot by lot.
Drought
89.8% 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 31 weeks, most recently on the September 15, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 99.9% |
| D1 moderate drought or worse | 89.8% |
| D2 severe or worse | 63.1% |
| D3 extreme or worse | 7.3% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Butte County since 2016.
Rain
| Average year, 1991-2020 | 12.78 in |
| 12 months to August 2026 | 11.66 in (-1.12) |
| 2025 | 12.58 in (-0.20) |
| Wettest year since 1895 | 1983: 20.67 in |
| Driest year since 1895 | 1924: 7.25 in |
| Days with 1 inch or more, normal at ARCO (7 mi away) | 0.2 |
Homes
| Housing units | 1,336 |
| Median year built | 1971 |
| Built before 1980 | 72% |
| Built 2000 or later | 10% |
| Owner-occupied | 78% |
| Median value, owner-occupied | $217,600 |
| Single-family detached | 74% |
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 |
|---|---|---|---|
| Jefferson County, ID | 44 mi | 21% | 8% |
| Blaine County, ID | 44 mi | 11% | 4% |
| Bingham County, ID | 51 mi | under 1% | 2% |
| Clark County, ID | 58 mi | 4% | 4% |
| Minidoka County, ID | 62 mi | 1% | 7% |
| Custer County, ID | 67 mi | 3% | 7% |
| Lincoln County, ID | 69 mi | 16% | 1% |
| Power County, ID | 71 mi | 1% | 2% |
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