By Dawn Construction. Updated November 2026.
When do roof leaks show up in Seattle, and what should you look for?
Most roof leaks in Seattle show up in late fall, when the long rainy season starts. Watch for ceiling stains, a damp or musty attic, missing or curling shingles, and moss. If you find a leak, catch the water, move valuables, take photos, and get the roof inspected before the next storm.
Seattle-Tacoma averages about 39 inches of rain a year, and most of it falls from fall through spring. A small gap that stayed dry all summer can let water in once the rain keeps coming day after day. That’s why the first weeks of the rainy season are the best time to check your roof, before a small leak turns into wet insulation, stained ceilings, or rotted wood.
What are the warning signs of a roof leak?
Some signs are inside the house, some are on the roof. You can spot most of them from the ground or from inside, without climbing up.
Inside your home
| What you notice | What it usually means |
|---|---|
| Brown or yellow stains on the ceiling | Water is getting through the roof and soaking the ceiling |
| Peeling paint or bubbling near the ceiling | Moisture is collecting behind the paint |
| A damp, musty smell in the attic or top floor | A slow leak or trapped moisture in the attic |
| Drips around a chimney, skylight, or vent pipe | The flashing (the metal seal around that opening) has failed |
| Wet or flattened insulation in the attic | Water has been coming in for a while |
Outside, from the ground
| What you notice | What it usually means |
|---|---|
| Missing, curling, or cracked shingles | Openings where wind-driven rain gets in |
| Thick moss on the roof | Moss holds water against the roof and can lift shingle edges |
| Granules (gritty sand) piling up in gutters | Shingles are wearing out |
| Gutters overflowing in rain | Water may be backing up under the roof edge |
| A sagging line along the roof | The wood under the shingles may be damaged |
What should you do the day you find a leak?
Stay safe first. Don’t climb on a wet roof; it’s slippery and dangerous, especially with moss.
- Catch the water. Put a bucket or container under the drip and lay down towels to protect the floor.
- Move what can get damaged. Electronics, furniture, rugs, and anything valuable.
- Watch for a bulging ceiling. If water is pooling in a sagging spot in the ceiling, it can give way. Keep people out from under it.
- Turn off power if water is near electrical fixtures. If water is coming through a light fixture or near outlets, switch off that circuit at the breaker.
- Take photos. Photograph the stains, the drip, and any damage. This helps with repairs and, if needed, your insurance claim.
- Check the attic if it’s safe. A flashlight can show where the water is coming in. That spot is often higher on the roof than the stain below.
- Call for an inspection before the next storm. The next long rain will keep making it worse.
Why do so many Seattle roofs leak?
Our climate is hard on roofs in a few specific ways.
- Long, steady rain: water keeps testing every weak spot for months at a time.
- Moss: shaded roofs under tall evergreens grow moss, which holds moisture against the roof and can lift shingle edges.
- Fir needles and leaves: they clog gutters and valleys (the channels where two roof slopes meet), so water backs up.
- Failed flashing: the metal seals around chimneys, skylights, vents, and walls are where most leaks start, not the shingles themselves.
- Trapped moisture in the attic: without enough ventilation, warm, damp air from the house can condense under the roof and look like a leak.
Should you repair or replace your roof?
Not every leak means a new roof. The roof’s overall condition decides.
| Situation | Usually the right move |
|---|---|
| One leak at a chimney, skylight, or vent; the rest of the roof is fine | Repair the flashing |
| A few missing or damaged shingles after a storm | Repair that area |
| Moss on one slope, but shingles still flat and solid | Moss removal and spot repairs |
| Leaks in several places, or leaks that keep coming back | Replacement is usually more cost-effective |
| Curling shingles and granules all over the roof | The roof is near the end of its life; plan a replacement |
| Soft or sagging spots | The wood underneath needs repair, usually with a replacement |
Can new shingles go over the old ones? Sometimes, but the building code doesn’t allow it when the existing roof is water-soaked or worn out, is wood shake, slate, or tile, or already has two or more layers. A full tear-off also lets the wood underneath be checked and repaired, which matters if there’s been a leak.
Do you need a permit to repair or replace a roof?
In Seattle, you don’t need a permit to replace roofing when no structural changes are made. Structural work, such as replacing damaged roof framing or adding a skylight, does need a permit. Other cities have their own rules, so we check yours and handle any permit.
How can you prevent leaks this winter?
A few simple steps go a long way:
| What to do | Why it helps |
|---|---|
| Clean gutters and downspouts in fall | Lets water leave the roof instead of backing up |
| Trim branches hanging over the roof | Less shade, less moss, fewer needles in the gutters |
| Have moss removed gently, not pressure-washed | Pressure washing can strip the protective granules off shingles |
| Check the attic after the first big storm | Catches small leaks before they spread |
| Get a roof inspection before winter | Finds failing flashing and loose shingles while they’re easy to fix |
FAQ
What should I do first if my roof is leaking?
Catch the water, move valuables away, take photos, and switch off power to any circuit where water is near a light or outlet. Then schedule a roof inspection before the next storm. Don’t climb on a wet roof.
Why does my roof leak only when it rains hard or for a long time?
Small gaps, often in flashing around chimneys, vents, or skylights, may stay dry in light rain but let water in during long or wind-driven storms. That’s common in Seattle’s rainy season.
Is moss bad for my roof?
Yes, over time. Moss holds water against the roof and can lift shingle edges, which lets water reach the layers underneath. Remove it gently; pressure washing can damage shingles.
Can a roof leak be repaired, or do I need a new roof?
Many leaks can be repaired, especially at flashing or a small damaged area. If the roof leaks in several places or the shingles are worn out across the roof, replacement is usually the better choice.
Do I need a permit to fix my roof in Seattle?
Not to replace roofing when no structural changes are made. Structural work, like replacing roof framing, needs a permit.
Can a new roof go over my old shingles?
Sometimes, but not if the roof is water-soaked or worn out, is wood shake, slate, or tile, or already has two or more layers. A tear-off is usually the better choice after a leak.
Found a leak or worried about your roof?
Dawn Construction inspects, repairs, and replaces roofs across Greater Seattle and the Puget Sound. Call (206) 672-1711 or book a free roof estimate, and we’ll find the source of the leak and tell you honestly whether it needs a repair or a new roof. See all our roofing services.
Sources
- NWS Seattle 1991–2020 climate normals (via Patch): https://patch.com/washington/seattle/new-climate-normals-seattle-area-warmer-wetter
- Seattle SDCI, Do You Need a Permit?: https://www.seattle.gov/construction-and-inspections/permits/do-you-need-a-permit
- ICC, 2021 International Residential Code, Chapter 9 (Section R908, re-roofing): https://codes.iccsafe.org/content/IRC2021P2/chapter-9-roof-assemblies