Glacier County, Montana
Shrink-swell clay limits houses without basements on 22% of Glacier County's mapped land, a higher share than 73% of US counties. A shallow water table limits basements on 2%.
The soil survey maps 80% 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. FEMA's flood data list no flood losses here since 2016. 63% of homes were built before 1980, against 50% nationally; the median home dates from 1974.
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 Glacier County
| Expansive clay (limits slab homes) | 22.3% |
| High water table (limits basements) | 2.1% |
| Septic fields very limited | 85.3% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 22.4% |
| Mapped soil | 1,538,584 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Fairfield | 8% | n/a |
| Williams | 8% | 0% |
| Leavitt | 5% | n/a |
| Martinsdale | 4% | n/a |
| Adel | 4% | n/a |
| Michelson | 4% | n/a |
How we count · survey areas MT600 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 4.5% by land area here, and 22% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 22% of the mapped land.
Rain over the 12 months to August 2026: 25.21 in, 1.14 in above the 1991-2020 average year of 24.07 in.
USDA rates 85% 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 43 of the last 52 weeks; the most was 100% of its area, in 7 weeks, most recently on the December 2, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Glacier County since 2016.
Rain
| Average year, 1991-2020 | 24.07 in |
| 12 months to August 2026 | 25.21 in (+1.14) |
| 2025 | 23.27 in (-0.80) |
| Wettest year since 1895 | 1899: 41.19 in |
| Driest year since 1895 | 1973: 15.14 in |
| Days with 1 inch or more, normal at CUT BANK MUNI AP (29 mi away) | 1.1 |
Homes
| Housing units | 5,350 |
| Median year built | 1974 |
| Built before 1980 | 63% |
| Built 2000 or later | 12% |
| Owner-occupied | 64% |
| Median value, owner-occupied | $165,100 |
| Single-family detached | 72% |
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 |
|---|---|---|---|
| Pondera County, MT | 48 mi | 35% | 4% |
| Flathead County, MT | 56 mi | 1% | 3% |
| Toole County, MT | 57 mi | 29% | 3% |
| Teton County, MT | 69 mi | 23% | 8% |
| Lake County, MT | 89 mi | 2% | 3% |
| Liberty County, MT | 90 mi | 34% | 3% |
| Lewis and Clark County, MT | 113 mi | 6% | 3% |
| Lincoln County, MT | 113 mi | n/a | n/a |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status