Sonoma County homes face water from every direction. Winter storms push rain through roofs and windows. The Russian River floods the lower river towns. The Laguna de Santa Rosa backs up around Sebastopol. The Petaluma River and its creeks rise in town. And inside the house, plumbing fails in every season. This guide pulls it together and links to deeper, sourced pages on each topic.
Why this winter deserves attention
NOAA's Climate Prediction Center (CPC) put an El Niño Advisory in effect, and its ENSO Diagnostic Discussion of October 8, 2026 says a strong-to-very strong El Niño is likely through January–March 2027, with better than an 83% chance. CPC is careful to add that, with an event this large, El Niño-type impacts are "larger, though not guaranteed." For Sonoma County, that means a wetter-than-normal winter is more likely, not certain. CPC's next update is due November 12, 2026.
The four big sources of water damage here
1. River and creek flooding
The Russian River at Guerneville has a flood stage of 32 feet, and the National Weather Service's river forecast center lists what floods at each level above that (CNRFC, Guerneville). In February 2019 the river crested at 45.38 feet, and Guerneville and Monte Rio saw roughly 2,000 properties with some flood damage (NWS). Healdsburg has its own gauge with a 23-foot flood stage (CNRFC, Healdsburg). Our deep dive on Russian River flood stages explains how to read them.
2. Storm runoff and hillside water
Intense rain sends water downhill into crawlspaces, garages and lower floors. Near burn areas, the City of Santa Rosa warns that flash floods and debris flows become more likely during intense rain (Santa Rosa Rain Ready).
3. Roof and window leaks
Wind-driven rain finds weak flashing, cracked tiles and old window seals. A small leak can soak attic insulation and ceiling drywall before anyone sees a stain. Our sister site covers roof prep for El Niño.
4. Plumbing failures
Burst supply lines, water heaters, dishwasher and washer hoses, and toilet supply lines cause year-round losses. See burst pipe water damage.
The first hour
- Safety. Stay out of water near outlets and appliances. Never walk or drive through floodwater.
- Stop the source. Close the main water valve for plumbing leaks. For outside flooding, protect people first.
- Document. Photograph and video everything before you move or throw anything away.
- Call. Contact your insurer and a restoration provider. The EPA says drying within 24 to 48 hours helps prevent mold (EPA).
Want a local pro to take a look?It's free for homeowners and there's no obligation.
How restoration works
Providers inspect and map moisture, extract water, remove materials that can't be saved, and dry the structure with air movers and dehumidifiers, logging readings daily. Floodwater and sewage call for more removal and cleaning. See the water damage drying process for the details, and emergency water removal if water is still standing.
Insurance basics
Sudden plumbing leaks are commonly covered by homeowners insurance, subject to your policy. Flooding generally isn't: SoCoEmergency notes that homeowners policies don't cover flood and that a flood policy typically takes up to 30 days to take effect (SoCoEmergency). Read our Sonoma County flood insurance guide.
Choosing a provider
Check licenses with CSLB. In a declared disaster area, unlicensed contracting is a felony, and CSLB advises paying no more than 10 percent down or $1,000, whichever is less (CSLB). Get the scope in writing, ask how drying will be documented, and know who handles rebuild. Here's how we vet providers.
Dealing with this right now?Tell us what's happening and we'll connect you with an independent local provider.
Local pages
We've written local pages where Sonoma County towns have specific water risks: river flood cleanup in Guerneville, Forestville, Healdsburg, Laguna flooding in Sebastopol, Petaluma River flooding and storm runoff in Santa Rosa. See all service areas.
Sources
- NOAA CPC ENSO Diagnostic Discussion, Oct 8 2026
- CNRFC: Russian River at Guerneville
- CNRFC: Russian River at Healdsburg
- NWS: Historic flooding across the North Bay, Feb 2019
- City of Santa Rosa: Rain Ready
- SoCoEmergency: Preparing for flood season
- EPA: A Brief Guide to Mold, Moisture and Your Home
- CSLB disaster guidance
- CSLB license check
Sources checked October 18, 2026.
Frequently asked questions
How do I know if water got into my walls?
Look for stains, bubbling paint, swollen baseboards and a musty smell. A provider can confirm with moisture meters and thermal imaging.
Is it OK to wait until after the weekend?
It's risky. The EPA says drying within 24 to 48 hours helps prevent mold. Calls are answered 24/7, so you don't have to wait to start.