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Ketchikan Gateway Borough, Alaska
A shallow water table limits basements on 47% of Ketchikan Gateway Borough's mapped land, a higher share than 64% of US counties and the 8th highest of 22 Alaska counties. Shrink-swell clay limits houses without basements on 0%.
None of the county is in drought on the November 3, 2026 Drought Monitor map. FEMA's flood data list 3 flood losses here since 2016. 57% of homes were built before 1980, against 50% nationally; the median home dates from 1977.
Data as of November 3, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, November 3, 2026
of homes built before 1980
Soil under Ketchikan Gateway Borough
| Expansive clay (limits slab homes) | 0.0% |
| High water table (limits basements) | 46.7% |
| Septic fields very limited | 70.7% |
| Clay swell (LEP, by area) | 1.5% |
| High-swell land (LEP 6%+) | 0.0% |
| Mapped soil | 3,645,843 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| McGilvery | 8% | n/a |
| St. Nicholas | 6% | n/a |
| Tolstoi | 6% | n/a |
| Kina | 6% | n/a |
| Karta | 5% | n/a |
| Kaikli | 4% | n/a |
How we count · survey areas AK644 (2025-08-29)
What the numbers mean here
On 47% of Ketchikan Gateway Borough'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: 144.83 in, 16.94 in below the 1991-2020 average year of 161.77 in.
USDA rates 71% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the November 3, 2026 map. Part of the county was in drought in 8 of the last 52 weeks; the most was 3.2% of its area, in 8 weeks, most recently on the September 22, 2026 map.
| Category, November 3, 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
3 flood losses since 2016, $7,916 paid. The worst year was 2025, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 1 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 2 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 161.77 in |
| 12 months to August 2026 | 144.83 in (-16.94) |
| 2025 | 161.96 in (+0.19) |
| Wettest year since 1925 | 1999: 198.11 in |
| Driest year since 1925 | 1995: 116.05 in |
| Days with 1 inch or more, normal at KETCHIKAN INTL AP (23 mi away) | 50 |
Homes
| Housing units | 6,698 |
| Median year built | 1977 |
| Built before 1980 | 57% |
| Built 2000 or later | 13% |
| Owner-occupied | 69% |
| Median value, owner-occupied | $393,300 |
| Single-family detached | 53% |
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 |
|---|---|---|---|
| Wrangell City and Borough, AK | 67 mi | 0% | 37% |
| Prince of Wales-Hyder Census Area, AK | 83 mi | 0% | 35% |
| Petersburg Borough, AK | 146 mi | n/a | n/a |
| Sitka City and Borough, AK | 207 mi | n/a | n/a |
| Juneau City and Borough, AK | 239 mi | 0% | 10% |
| Hoonah-Angoon Census Area, AK | 277 mi | 0% | 21% |
| Haines Borough, AK | 308 mi | 0% | 25% |
| Skagway Municipality, AK | 334 mi | 0% | 27% |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status