Floods on the river are routine, but not small
The National Weather Service's forecast center lists flood stage for the Russian River at Guerneville at 32 feet, with major flooding at 40 feet; the record is 49.5 feet, set in February 1986 (CNRFC). In February 2019 the river crested at 45.38 feet and the NWS counted roughly 2,000 properties with some damage around Guerneville and Monte Rio (NWS). The County estimated about 1,900 homes damaged countywide (County of Sonoma).
Why river floods are a mold problem
- Contaminated water. River floodwater carries sewage, fuel and debris. The EPA advises professionals experienced with contaminated water (EPA).
- Long soak times. Homes can sit in water for a day or more, and road closures can keep owners out longer. CDPH says porous materials wet for more than a day or two may need removal even before mold shows (CDPH).
- Silt and mud hold moisture against framing and in crawlspaces.
- Damp, shaded sites under redwoods dry slowly even after the water's gone.
When you get back in
- Wait for officials to allow re-entry. Check for gas smells, electrical hazards and structural damage.
- Wear boots, gloves, goggles and an N-95 respirator (CDPH).
- Photograph everything before you move it.
- Shovel out mud and remove soaked carpet, pad, insulation and drywall, typically well above the water line.
- Open walls to let cavities dry; get fans and dehumidifiers running once power is safe.
- Scrub hard surfaces with detergent and water (EPA).
- Don't close up walls until framing is verified dry.
Want a local pro to take a look?It's free for homeowners and there's no obligation.
Crawlspaces and raised homes
Many river homes are raised or sit over crawlspaces. Mud and water under the house need to be removed and the space dried; wet insulation in the floor system usually has to come out. See crawlspace mold.
Local pages
- Mold after floods in Guerneville, Monte Rio and Rio Nido
- Russian River flood cleanup on Sonoma County Water Damage
- Storm roof repair on the lower river
Sources
- CNRFC: Russian River at Guerneville
- NWS: Historic flooding across the North Bay, Feb 2019
- County of Sonoma: flood damage estimate, Mar 2019
- EPA: Mold cleanup in your home
- CDPH: Frequently asked questions about mold
Sources checked October 18, 2026.
Frequently asked questions
Can I clean up after a river flood myself?
You can do some of the work with proper protection, but contaminated floodwater and large areas of damage are jobs the EPA recommends for experienced professionals.
How high should drywall be cut?
Providers often cut above the water line so wet insulation and wicking moisture come out. The exact height depends on the water level and how far moisture wicked.