Few places in California know floods like the lower Russian River. If you live here, you probably know your house's number: the river level where water reaches your street. This page pulls together the official local information and what to do when the river goes down.
What floods at each level
The CNRFC's impact table for the Guerneville gauge is specific (CNRFC):
- 32 ft (flood stage): Lower Mill Street in Guerneville and Old Bohemian Highway in Monte Rio.
- 33 ft: Highway 116 at Drake Road in Guerneville closes; Willow and Alder Streets in Monte Rio flood.
- 34 to 35 ft: Flooding begins at riverside resorts and Riverside Park; at 35 ft, numerous businesses and residences in the lowest parts of river towns.
- 39 ft: River Road floods in Hacienda; Canyon 7 Road in Rio Nido floods.
- 41.5 ft: River Road closes in Guerneville; Monte Rio's main intersections flood.
- 44 to 46 ft: Highway 116 west of town closes; much of downtown Guerneville floods; River Road in Rio Nido floods.
2019 as a benchmark
On February 27, 2019, the river crested at 45.38 feet. Guerneville and Monte Rio were cut off, and the NWS counted roughly 2,000 properties with some flood damage (NWS). Countywide, the County estimated $155 million in damage, including about 1,900 homes (County of Sonoma).
Before the river rises
- Sign up for SoCoAlert and keep the Sonoma Water Flood Forecast Hotline, (707) 526-4768, in your phone.
- Move vehicles, belongings and documents above your known flood level early. Roads close before homes flood.
- Pick up sandbags early. The County has listed the Monte Rio Fire Department, 9870 Main St., as a station (SoCoEmergency).
Want a local pro to take a look?It's free for homeowners and there's no obligation.
When you go back in
- Wait for the all-clear. Road closures can outlast the water.
- Check for gas leaks and electrical hazards before you go inside.
- Photograph the water line and every room.
- Start removing soaked materials quickly. Floodwater is contaminated, and the EPA says drying within 24 to 48 hours usually prevents mold (EPA).
- Get the crawlspace pumped and dried. Mud left under the house keeps humidity high for weeks.
Permits and contractors
Repairs in unincorporated river communities go through Permit Sonoma. Verify contractors at CSLB; unlicensed contracting in a declared disaster area is a felony (CSLB).
Related
- Russian River flood stages explained
- Returning home after a flood
- Mold after a Russian River flood on Sonoma Mold Removal
- Storm roof repair on the lower river on Sonoma Roof Repair
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Sources
- CNRFC: Russian River at Guerneville
- NWS: Historic flooding across the North Bay, Feb 2019
- County of Sonoma: flood damage estimate, Mar 2019
- SoCoEmergency: Sandbags
- Sonoma Water: Flood forecast
- EPA mold guide
- CSLB disaster guidance
Sources checked October 18, 2026.
Frequently asked questions
How soon can cleanup start?
As soon as officials allow re-entry and it's safe. The sooner wet materials come out, the better the odds of avoiding mold.
Do restoration crews work during road closures?
Crews have to wait until roads open like everyone else. Calling early gets you in the queue.