Key facts: Seattle
- Seattle's rain is steady, not dramatic, but in December 2022 a record tide pushed the Duwamish into South Park homes.[1]
- Hillside houses collect runoff against the uphill wall.
- Older basements were rarely waterproofed, so seepage appears after weeks of rain.
Slow rain, steep lots
Hillside houses collect runoff against the uphill wall. Older basements were rarely waterproofed, so seepage appears after weeks of rain.
Crawl spaces and mold
Cool, damp air slows drying. Vapor barriers and ventilation matter, and a musty smell in winter deserves a look.
Flood claims recorded in King County
Seattle sits in King County. FEMA publishes every National Flood Insurance Program claim with personal details removed, which gives a plain record of where water has reached insured buildings here.
| Measure | Count |
|---|---|
| Flood insurance claims on record | 3,384 |
| Year with the most claims | 2009 (668) |
| Largest named event | Flooding (793) |
| Claims outside high-risk A and V zones | 29% |
| Claims on buildings built before 1975 | 69% |
County-wide counts of insured claims only. Uninsured losses, burst pipes and appliance leaks are not in this data.
What the Seattle claim record shows
For Seattle homes, the local precedents are the events behind the most King County claims: Flooding (793 claims), Torrential Rain (410 claims) and 2025-12-Atmosphericriver (203 claims).
About 29% of claims with a recorded zone came from outside the high-risk A and V zones, so a moderate-risk label does not mean a Seattle home stays dry.
If your Seattle home is older, note that buildings from before 1975 make up 69% of county claims with a known build date. Many predate current flood maps, so inspect low outlets, ductwork and subfloors closely after any water event.
Federal disaster history for King County
FEMA lists 35 federal declarations covering King County. The most common types are flood (17), severe storm (11) and biological (2). The latest are Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in 2025, Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in 2024 and Bolt Creek Fire in 2022. If your loss falls inside an open declaration, Seattle homeowners can check DisasterAssistance.gov as well as their insurance policy.
Seattle weather and your home
Weather records for Seattle from 2015 through 2024 average 47 inches of precipitation a year, and December and January are the wettest months. The area averages 5.9 days a year with an inch or more.
Frost reaches Seattle on about 23 nights a year, but hard freezes are less common, which can leave pipes in attics and outer walls poorly protected in a cold snap.
When rain falls in Seattle
Seasonal averages for Seattle, 2015 through 2024. Plan roof, gutter and sump pump checks before the wettest stretch.
| Season | Average | Share of year |
|---|---|---|
| January to March | 16.5 in | 35% |
| April to June | 7.4 in | 16% |
| July to September | 4.1 in | 9% |
| October to December | 19.3 in | 41% |
Modeled from Open-Meteo historical weather data. Precipitation includes rain and melted snow.
Seattle home checklist from these records
- Don't rely on recent quiet years. Only 16% of King County claims date from 2015 or later, so older floods still show what can happen.
- Check roof flashing and drains before December, the wettest month in Seattle.
- Keep dated photos of each room. After Flooding, 793 insured King County owners filed claims at about the same time.
What to tell the Seattle contractor
- Your neighborhood
- Whether the home is on a slope
- Whether water is seeping or rising
Services Seattle callers ask about
Questions
Seattle water damage questions
Do you cover Bellevue?
Yes, along with Renton and Kent.
Is seepage an emergency?
Usually not, unless it's near electrics or spreading.