A Sebastopol environmental watchdog group has threatened to sue Sonoma Water and the small sewer district it operates in Guerneville over alleged water quality violations tied to a massive, multi-day spill of wastewater during a heavy storm this past January. A March 18 letter from local attorney Jack Silver, representing the nonprofit California River Watch, accuses the county water agency and Russian River Sanitation District of violations of the federal Clean Water Act. The notice of intent to sue comes three months after an estimated 5.5 million gallons of wastewater, including untreated sewage, overflowed from the district’s Guerneville treatment plant into the lower Russian River over three days, making for the largest such spill in the river in more than four decades.

Other water pollution news:

• Environment America: News release: Lawsuit alleges quarry operator Granite Rock Company illegally polluted Pajaro River
• Ebb and Flow (California Water Boards): Blog: Rainstorms after wildfires: Erosion can threaten water quality for years