Cascade County, Montana
Shrink-swell clay limits houses without basements on 35% of Cascade County's mapped land, a higher share than 84% of US counties and the 10th highest of 53 Montana counties. A shallow water table limits basements on 2%.
The soil survey maps 89% of the county's land area; these shares describe the mapped part. None of the county is in drought on the October 13, 2026 Drought Monitor map, after 0.3% a week earlier. FEMA's flood data list 18 flood losses here since 2016. 66% of homes were built before 1980, against 50% nationally; the median home dates from 1970.
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 Cascade County
| Expansive clay (limits slab homes) | 34.8% |
| High water table (limits basements) | 2.0% |
| Septic fields very limited | 88.0% |
| Clay swell (LEP, by area) | 4.6% |
| High-swell land (LEP 6%+) | 34.9% |
| Mapped soil | 1,533,474 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Castner | 5% | n/a |
| Hilger | 5% | n/a |
| Absarokee | 4% | n/a |
| Cheadle | 3% | n/a |
| Libeg | 3% | n/a |
| Perma | 2% | n/a |
How we count · survey areas MT613 (2025-08-30)
What the numbers mean here
Clay swell averages a linear extensibility of 4.6% by land area here, and 35% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 35% of the mapped land.
Rain over the 12 months to August 2026: 16.81 in, 0.23 in below the 1991-2020 average year of 17.04 in.
USDA rates 88% 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 51 of the last 52 weeks; the most was 100% of its area, in 15 weeks, most recently on the June 23, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 1.9% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
18 flood losses since 2016, $304,435 paid. The worst year was 2018, with 9.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 1 |
| 2018 | 9 |
| 2019 | 4 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 1 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 17.04 in |
| 12 months to August 2026 | 16.81 in (-0.23) |
| 2025 | 14.54 in (-2.50) |
| Wettest year since 1895 | 1975: 27.27 in |
| Driest year since 1895 | 1935: 9.86 in |
| Days with 1 inch or more, normal at GREAT FALLS INTL AP (11 mi away) | 1 |
Homes
| Housing units | 39,497 |
| Median year built | 1970 |
| Built before 1980 | 66% |
| Built 2000 or later | 18% |
| Owner-occupied | 69% |
| Median value, owner-occupied | $265,300 |
| Single-family detached | 67% |
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 and Clark County, MT | 51 mi | 6% | 3% |
| Judith Basin County, MT | 53 mi | 37% | 4% |
| Meagher County, MT | 54 mi | n/a | n/a |
| Teton County, MT | 55 mi | 23% | 8% |
| Chouteau County, MT | 58 mi | 39% | 2% |
| Broadwater County, MT | 69 mi | 1% | 3% |
| Pondera County, MT | 74 mi | 35% | 4% |
| Powell County, MT | 81 mi | 10% | 6% |
Sources: USDA SSURGO (August 30, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status