EPA Joins Investigation Of Marin Sewage Spills

The U.S. Environmental Protection Agency is investigating two wastewater spills that occurred in Marin County last month, according to Ross Valley Sanitary District officials.

A spill in Kentfield on Dec. 17 and 18 and an overflow in Larkspur on Dec. 22 were estimated at 2.6 million gallons. The spills were a mixture of sewage and rainwater.

District officials said the 842,000-gallon spill, in which wastewater poured from manholes in Kentfield into Corte Madera Creek, was caused by large amounts of construction debris that clogged the district's pump station and sewer pipes.

The debris was from a $4 million sewer system improvement project by JMB Construction Inc. of South San Francisco, district general manager Brett Richards said.

Richards said the debris got into the sewer system through either severe negligence or malicious intent.

Richards said the larger spill in Larkspur was caused by the failure of a 36-inch diameter Techite pipe that runs underground along a jogging path in Larkspur.

The EPA is investigating the cause of the spills, the district's response, and construction practices, district officials said in a news release.

The district said it would release a detailed timeline of the two spills and its response for public review when the EPA releases its findings.

District officials also said Wednesday afternoon that about 20 signs advising residents not to swim, drink from or allow pets in the Corte Madera Creek have been stolen or removed since the spills.

"It's a little vexing. We're trying to advise the public and do our due diligence," district business manager Wendy Martin-Miller said.

Martin-Miller said Twin Cities police have been notified about the missing signs, and the district is working to replace them.