Russian River Wastewater Spill Is Halted After Sonoma County Storms

A wastewater spill that spurred warnings to stay out of the Russian River this week after a storm drenched Sonoma County was stopped Thursday morning, officials said.

Tuesday’s heavy rainfall overwhelmed a local wastewater treatment facility, the Russian River Treatment Plant in Guerneville, which received flows at a rate of around 4 million gallons per day — nearly six times its average dry-weather design of 710,000 gallons. With no additional storage available, millions of gallons of untreated wastewater traveled roughly a quarter-mile through a forested redwood grove before entering the mainstem of the river.

Sonoma Water spokesperson Stuart Tiffen told KQED that the spill persisted Wednesday as the river continued to run high.

The spill was officially stopped at 6:50 a.m. Thursday, though warnings to stay out of the water remain in effect, according to Sonoma Water. District staff are now assessing the total volume of untreated wastewater released and are preparing reports for state regulatory agencies. Tiffen noted that a final estimate will not be available until those reports are submitted, adding that the massive volume of stormwater in the river makes testing for pathogens more difficult.

“It’s complicated by the amount of storm water and how that would affect testing regardless of a spill,” Tiffen said. “Because it tends to muddy the water, so to speak.”

County officials posted warning signs at river access points and coastal beaches from the Marin to Mendocino border. Residents and visitors were urged to avoid all contact with the water, which may contain bacteria, viruses and other pathogens that pose serious health risks.

Sonoma County Supervisor Lynda Hopkins said turbidity levels in the river were too high to deploy the facility’s ultraviolet sanitization system, which is used to disinfect the water.

“In my opinion, this facility was built poorly in the first place and was never equipped to really handle the amount of rain that we can get,” Hopkins said. “We just simply do not have the capacity to handle these severe atmospheric storm events.”

The Russian River County Sanitation District, which began operations in 1983, serves approximately 3,200 households. Hopkins noted that because the service area is small, the multimillion-dollar costs for necessary infrastructure upgrades would fall on a limited number of customers who already pay some of the highest sewer rates in the state.

“We’re really going to be looking to state and federal funds to try to come up with a long-term solution,” Hopkins said. “We need to use that sense of urgency to drive towards a bigger picture, longer-term solutions for the lower Russian River as a whole.”

As of Thursday, the Sonoma County Department of Environmental Health is continuing to coordinate water quality testing to determine when it will be safe for the public to return to the river.