Video from Sewerage Agency of South Marin shows a tree root burst through a 12-inch sewer pipe that is supposed to be water tight. The video was shot with a special camera extended 176 feet into a pipe that runs underneath Mill Valley's Almonte Boulevard. This is just one example of what is ailing the Bay Area's 17,000 miles of leaky sewer lines.
"In 2007, we had almost 2,000 spills contributing 12 million gallons of raw sewage to our streets and creeks," said Sejal Choksi with the environmental watchdog group San Francisco Baykeeper.
Much of that flows straight into the San Francisco Bay. It is an amount 240 times greater than the oil spilled by the Cosco Busan last year. Besides human waste, raw sewage contains trash, oil, ammonia, metals and discarded pharmaceuticals and personal care products.
"If the bay keeps getting slammed, especially during wet weather, from bacteria and pathogens and industrial chemicals, the stuff that you find in these sewage spills, then it's going to have an impact in the long-term," said Choksi.
Most of the spillage comes from aging pipes that are often caked with grease and marred with cracks and gaping holes. It is part of an infrastructure that in some places is 50 to 100 years old.
According to the San Francisco Bay Regional Water Quality Control Board, the Bay Area has a sewage spill rate that is more than double the statewide average.
"It's easy if you don't see a problem just to sort of say it doesn't exist. And so we do find that there are some agencies who are just keeping their rates the same, doing little on maintenance, doing little on upgrade and then bam, we have a problem," said Bruce Wolfe with the San Francisco Regional Water Quality Control Board.
Stephen Danehy is the general manager of the Sewerage Agency of Southern Marin, home to a wastewater treatment plant. It is a facility that failed massively during heavy storms last winter. In January, the plant spilled nearly 3.5 million gallons of sewage into Richardson Bay in two incidents over a six-day period.
"We simply got too much water into the plant. The plant just couldn't handle any more flow at that time," said Danehy. "We also had some old age issues with some of our equipment and control systems."
Beaches in Tiburon and San Francisco had to be closed for several days. The state water board fined Southern Marin $1.6 million and the U.S. Environmental Protection Agency stepped in.
"We did issue some enforcement orders against the systems there in Southern Marin County, requriing them to make some improvements to their systems," said Ken Greenberg with the U.S. Environmental Protection Agency.
Over the summer, Southern Marin installed flow monitors throughout its network and doubled the capacity of its two storage ponds.
In a further effort to prevent the type of spills they had last winter, the agency in Southern Marin also rebuilt or replaced all of its pumps. They were 25 years old and so rusty and corroded, there was nothing to salvage.
"Between our alarm notification system, our new pumping equipment, our new pumping controls, I feel much more comfortable than I did last year, definitely," said Danehy.
But Danehy admits, he still worries about all the old pipes from six different agencies that drain into his facility.