Water under the house is easy to miss and slow to leave. It raises humidity indoors, soaks floor framing and insulation, and can lead to mold. Here's how that plays out in Guerneville & the lower Russian River, what to do right now, and how to reach an independent, licensed local provider. Call (628) 336-1777 any time, or use the form on this page.
Crawlspace flooding in Guerneville: what we see
On the lower Russian River, river water under the house is part of big winters. Flood stage at the Guerneville gauge is 32 feet, and in February 2019 the river crested at 45.38 feet (CNRFC; NWS). Many homes are raised, and their crawlspaces fill with river water and silt that must come out before drying can start.
The local picture
Slopes and runoff. Where water comes from depends on where the house sits. Guerneville spans the narrow lower Russian River canyon, with steep wooded slopes and low river flats.
Creeks, tides and groundwater. Proximity to water affects groundwater and flood risk under the house. Guerneville is shaped by the Russian River, which floods low areas in big winters.
Neighborhoods include Guerneville, Monte Rio, Rio Nido and the other lower river communities. Conditions vary from street to street, so a provider should look at your specific home rather than assume.
What to do right now
- Don't enter a flooded crawlspace if wiring may be wet or if the water could be sewage or floodwater.
- Photograph the water level from the access hatch.
- Check your sump pump and its power, if you have one.
- Fix obvious sources you can reach safely, like a disconnected downspout.
- Call for professional pumping and drying.
Want a local pro to take a look?It's free for homeowners and there's no obligation.
Guerneville checklist
- Know the river level at which water reaches your property.
- Clean gutters and extend downspouts well away from the foundation.
- Make sure soil slopes away from the house.
- Check that the vapor barrier covers the soil and isn't torn.
- Look under the house after the first big storm of the season.
Local resources for Guerneville
- Permits: Permit Sonoma (unincorporated county)
- Emergency alerts: SoCoAlert, the County's free notifications
- Sandbags: Sonoma County sandbag locations, updated during weather events
- Contractor licenses: CSLB license check
How a provider handles it
Providers pump out the water, remove wet insulation and damaged vapor barrier, clean framing (and treat it after contaminated water), and dry with dehumidifiers while monitoring moisture in the wood. Lasting fixes usually involve drainage work. For the full picture, read our complete guide and the deep dive After a flood: cleanup safety. We also have a storm-season article: How to use sandbags.
Before you hire anyone, check the license on the CSLB site. 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.
More for Guerneville
- Water damage in Guerneville & the lower Russian River: our full local page
- Crawlspace flooding service
- Russian River flood cleanup in Guerneville, Monte Rio and Rio Nido: our in-depth local guide
- Burst pipe water damage in Guerneville
- Sewage backup cleanup in Guerneville
- Storm and flood damage in Guerneville
- Appliance and water heater leaks in Guerneville
- Same problem nearby: crawlspace flooding in Forestville, crawlspace flooding in Sebastopol, crawlspace flooding in Healdsburg
- Crawlspace flooding in every Sonoma County town
Sources
- SoCoAlert sign-up
- Sonoma County sandbag locations
- FEMA Flood Map Service Center
- CDC: flood safety
- CSLB license check
Sources checked October 18, 2026.
Frequently asked questions
When is it safe to go under the house after a flood?
Wait until water has receded, power has been checked, and you have boots, gloves and a respirator. Treat floodwater and silt as contaminated.
Is water in the crawlspace covered by insurance?
It depends on the cause. A sudden plumbing failure is treated differently from groundwater or outside flooding. Check your policy.
Will this cause mold?
Damp crawlspaces are a common source of mold. Dry it out and fix the source. See our sister site's crawlspace mold guide.