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U.S. EPA releases inspection reports for South Marin sewage collection systems

Release Date: 02/12/2008
Contact Information: Wendy Chavez, 415/947-4248,

(San Francisco, Calif. -- 02/12/2008) Following the recent large sewage spills to the San Francisco Bay from a Marin County treatment plant, the U.S. Environmental Protection Agency today finalized and released inspection reports for five of six sewage collection systems that flow to the Sewerage Agency for Southern Marin wastewater facility.

The EPA’s October inspections confirmed that the sewage collection systems for Almonte, Tamalpais, Alto, Homestead Valley and Richardson Bay have significantly deteriorating sewage pipes that are overwhelmed by rainwater during wet weather, which affect operations of the Sewerage Agency for Southern Marin plant and its discharge to San Francisco Bay waters.

“The public may be surprised to learn we have many neglected sewage collection systems, which are small, underfunded and undermanaged. These systems will continue to pose threats to San Francisco Bay if communities fail to upgrade and maintain their systems sustainably,” said Alexis Strauss, the EPA’s Water Division director for the Pacific Southwest region. “We at the EPA will continue, as we've done elsewhere in California, to work with the California Regional Water Quality Control Boards and the systems directly to achieve long-overdue assessment, repair and replacement.”

“The best way to deal with sewer spills is to prevent them from ever occurring,” said John Muller, chair to the San Francisco Bay Regional Water Board. “I would prefer to work with local government and other leaders to make sure the Bay Area has the finest infrastructure possible. That is how we all should protect water quality.”

On Friday the Regional Water Board issued an order to the SASM requiring a full report on the recent spills to the Bay, and requiring the agency to audit its operations. The audit report is due April 7.

Deteriorating pipes, combined with extreme peak flows from rainwater, overwhelmed the SASM facility, causing the Jan. 25 flows to exceed capacity at the emergency holding basins at the plant, and overflowed to San Francisco Bay waters. The subsequent Jan. 31 spill occurred when the treatment plant failed to operate all of its discharge pumps designed to achieve higher levels of treatment offsite, thus also leading to another spill to Bay waters.

When sewage spills occur, prompt posting of affected beaches is required to protect the public. County health departments should be prepared to post waterways immediately when these types of discharges occur.

The Sewerage Agency of Southern Marin treats wastewater from about 28,000 people in the Mill Valley area. The sewage is collected from homes and businesses in networks of sewer pipes that are owned and maintained by five separate sanitary districts and the city of Mill Valley.

To view the inspection reports, please visit: