Tillamook County, Oregon
USDA's soil survey flags shrink-swell clay on 1% of Tillamook County's mapped land and a shallow water table under basements on 5%, both below the national shares of 15% and 29%. None of the county is in drought on the October 13, 2026 Drought Monitor map.
FEMA's flood data list 37 flood losses here since 2016, 7% of them in buildings with basements. 50% of homes were built before 1980, against 50% nationally; the median home dates from 1980.
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 Tillamook County
| Expansive clay (limits slab homes) | 0.6% |
| High water table (limits basements) | 5.5% |
| Septic fields very limited | 96.2% |
| Clay swell (LEP, by area) | 2.0% |
| High-swell land (LEP 6%+) | 1.6% |
| Mapped soil | 720,147 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Klootchie | 12% | n/a |
| Klistan | 10% | n/a |
| Necanicum | 10% | n/a |
| Hemcross | 10% | n/a |
| Templeton | 7% | n/a |
| Harslow | 5% | n/a |
How we count · survey areas OR057 (2025-09-09)
What the numbers mean here
Rain over the 12 months to August 2026: 95.53 in, 5.55 in below the 1991-2020 average year of 101.08 in.
USDA rates 96% of the land very limited for septic absorption fields.
With shrink-swell clay on 1% and a shallow water table on 5% of the land, the soil survey points to neither problem across most of Tillamook County; conditions still vary lot by lot.
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 8 of the last 52 weeks; the most was 100% of its area, on the October 21, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 37.8% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
37 flood losses since 2016, $393,891 paid. The worst year was 2021, with 12. Foundations of the buildings, where recorded: 7% basements, 30% slabs, 37% crawl spaces, 26% elevated.
| Year | Flood losses |
|---|---|
| 2016 | 4 |
| 2017 | 5 |
| 2018 | 8 |
| 2019 | 0 |
| 2020 | 1 |
| 2021 | 12 |
| 2022 | 0 |
| 2023 | 3 |
| 2024 | 1 |
| 2025 | 3 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 101.08 in |
| 12 months to August 2026 | 95.53 in (-5.55) |
| 2025 | 92.41 in (-8.67) |
| Wettest year since 1895 | 1996: 145.93 in |
| Driest year since 1895 | 1929: 58.89 in |
| Days with 1 inch or more, normal at TILLAMOOK (4 mi away) | 24.6 |
Homes
| Housing units | 19,213 |
| Median year built | 1980 |
| Built before 1980 | 50% |
| Built 2000 or later | 24% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $430,200 |
| Single-family detached | 77% |
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 |
|---|---|---|---|
| Yamhill County, OR | 26 mi | 31% | 36% |
| Washington County, OR | 33 mi | 7% | 42% |
| Clatsop County, OR | 39 mi | 1% | 12% |
| Polk County, OR | 42 mi | 18% | 30% |
| Columbia County, OR | 47 mi | 7% | 35% |
| Lincoln County, OR | 57 mi | 1% | 6% |
| Wahkiakum County, WA | 62 mi | 4% | 10% |
| Clark County, WA | 65 mi | 3% | 22% |
Sources: USDA SSURGO (September 9, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status