Boundary County, Idaho
A shallow water table limits basements on 24% of Boundary County's mapped land and the 4th highest of 43 Idaho counties. Shrink-swell clay limits houses without basements on under 1%.
86.3% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 34% of homes were built before 1980, against 50% nationally; the median home dates from 1991.
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 Boundary County
| Expansive clay (limits slab homes) | 0.1% |
| High water table (limits basements) | 23.7% |
| Septic fields very limited | 90.6% |
| Clay swell (LEP, by area) | 1.4% |
| High-swell land (LEP 6%+) | 3.2% |
| Mapped soil | 809,021 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Pend Oreille | 4% | n/a |
| Idamont | 3% | n/a |
| Rubson | 3% | n/a |
| Jeru | 2% | n/a |
| Prouty | 2% | n/a |
| Schnoorson | 2% | n/a |
How we count · survey areas ID601 (2025-08-27), ID604 (2025-08-27), ID670 (2025-08-27)
What the numbers mean here
On 24% of Boundary 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: 35.92 in, 2.99 in below the 1991-2020 average year of 38.91 in.
USDA rates 91% of the land very limited for septic absorption fields.
Drought
86.3% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 40 of the last 52 weeks; the most was 100% of its area, in 17 weeks, most recently on the September 29, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 86.3% |
| D2 severe or worse | 44.3% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $0 paid. The worst year was 2017, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 38.91 in |
| 12 months to August 2026 | 35.92 in (-2.99) |
| 2025 | 38.73 in (-0.18) |
| Wettest year since 1895 | 2012: 58.03 in |
| Driest year since 1895 | 1944: 19.70 in |
| Days with 1 inch or more, normal at BONNERS FERRY (13 mi away) | 1.6 |
Homes
| Housing units | 5,615 |
| Median year built | 1991 |
| Built before 1980 | 34% |
| Built 2000 or later | 37% |
| Owner-occupied | 75% |
| Median value, owner-occupied | $410,500 |
| Single-family detached | 80% |
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 |
|---|---|---|---|
| Bonner County, ID | 29 mi | under 1% | 14% |
| Pend Oreille County, WA | 32 mi | 0% | 11% |
| Lincoln County, MT | 53 mi | n/a | n/a |
| Stevens County, WA | 63 mi | 0% | 8% |
| Kootenai County, ID | 73 mi | 2% | 10% |
| Spokane County, WA | 86 mi | 3% | 16% |
| Ferry County, WA | 91 mi | under 1% | 4% |
| Sanders County, MT | 94 mi | 2% | 3% |
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