Teton County, Idaho
USDA's soil survey flags shrink-swell clay on 5% of Teton County's mapped land and a shallow water table under basements on 12%, both below the national shares of 15% and 29%. 98.5% of the county is in drought on the October 13, 2026 Drought Monitor map, down from 100% a week earlier.
FEMA's flood data list 1 flood losses here since 2016. 19% of homes were built before 1980, against 50% nationally; the median home dates from 2001.
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 Teton County
| Expansive clay (limits slab homes) | 5.2% |
| High water table (limits basements) | 12.2% |
| Septic fields very limited | 85.5% |
| Clay swell (LEP, by area) | 3.3% |
| High-swell land (LEP 6%+) | 5.9% |
| Mapped soil | 288,083 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Alpine | 10% | n/a |
| Koffgo | 9% | n/a |
| Kucera | 7% | n/a |
| Ririe | 6% | n/a |
| Edgway | 4% | n/a |
| Lostine | 3% | n/a |
How we count · survey areas ID650 (2025-08-27), ID758 (2025-08-27)
What the numbers mean here
Rain over the 12 months to August 2026: 22.23 in, 2.58 in below the 1991-2020 average year of 24.81 in.
USDA rates 85% of the land very limited for septic absorption fields.
With shrink-swell clay on 5% and a shallow water table on 12% of the land, the soil survey points to neither problem across most of Teton County; conditions still vary lot by lot.
Drought
98.5% 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 51 weeks, most recently on the October 6, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 98.5% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $14,064 paid. The worst year was 2023, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 1 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 24.81 in |
| 12 months to August 2026 | 22.23 in (-2.58) |
| 2025 | 22.78 in (-2.03) |
| Wettest year since 1895 | 1983: 33.78 in |
| Driest year since 1895 | 1898: 15.03 in |
| Days with 1 inch or more, normal at TETONIA EXP STN (7 mi away) | 0.9 |
Homes
| Housing units | 6,481 |
| Median year built | 2001 |
| Built before 1980 | 19% |
| Built 2000 or later | 55% |
| Owner-occupied | 81% |
| Median value, owner-occupied | $690,500 |
| Single-family detached | 76% |
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 |
|---|---|---|---|
| Madison County, ID | 22 mi | under 1% | 14% |
| Bonneville County, ID | 33 mi | 11% | 4% |
| Fremont County, ID | 34 mi | 1% | 6% |
| Teton County, WY | 44 mi | 7% | 6% |
| Jefferson County, ID | 55 mi | 21% | 8% |
| Clark County, ID | 68 mi | 4% | 4% |
| Caribou County, ID | 70 mi | 13% | 4% |
| Bingham County, ID | 70 mi | under 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