Cities Slipping Raw Sewage into Bay Waters

You may want to watch where you swim.

The environmental stewards at San Francisco Baykeeper recently sued San Mateo County over a dirty little secret: the waste that you flush down the drain doesn't always get treated. Sometimes, it's pumped right out into the bay.

It took eight lawsuits and two years, but San Mateo is finally ponying up the cash required to upgrade its aging sewer system. Heavy rains are the biggest problem: when millions of gallons of stormwater enter the system, the treatment plants exceed their capacity and have to dump the water somewhere: either let it back up into city streets, or dump it on unsuspecting fish.

At the height of the last rainy season, there were thirty such spills in one month, contributing hundreds of thousands of gallons of pollution to the bay.

The first step is to install meters in the system to determine where the overload is worst. A pipe-cleaning truck and exhaustive inspection will also eliminate clogs and leaks.

All told, the work is expected to cost around $13 million. That means higher water rates, but also a water system that's safer and more sanitary.

The goal of Baykeeper is to reduce the spills from sixty a year to four by 2017. It's an ambitious goal, but one that could be attainable through a combination of sewer upgrades and low-impact design elements such as bioswales, living roofs, rainwater catchment tanks, and street trees.

In the late 1970s, San Francisco was hit with an enforcement action by the EPA for the volume of its sewage discharges. The solution was a ring of underground chambers encircling the entire city, which fill with rainwater during the wet season so that the treatment plants have time to deal with it all. The city reduced its overflows from around thirty a year to around a dozen.