Let’s Talk About San Francisco’s Sewer System

San Francisco’s sewer system became a trending topic overnight after statements were made about how the City manages wastewater and stormwater.

The SFPUC is always looking for ways to educate people about the City’s drainage system, so this seems like a good time to break down what the Agency does to protect public health and the environment.

Southeast Treatment Plant. Aerial view. Photo taken in 1990.
Southeast Treatment Plant, aerial view of digesters. Taken in 1996

San Francisco is the only coastal city in California that operates a combined sewer system. That means that the City collects and treats both wastewater (what’s flushed down the toilet, goes down the sink or bathroom drain) and stormwater. Stormwater enters the combined sewer system through building roof drains or the catch basins at almost every street corner and gets treated at San Francisco’s treatment plants just like the wastewater that goes down the bathroom drain.

Debris and other street litter that you see on the street goes through multiple layers of treatment, beginning with catch basins and ending at the City’s treatment plants ensuring they are removed before discharging to the bay or ocean.

A view of the egg-shaped digesters at Oceanside Treatment Plant. Photo taken in 2011.
A view of San Francisco Bay.

San Francisco’s sewer system treats billions of gallons of stormwater and wastewater each year.

And the SFPUC collaborates with both state and federal Clean Water Act regulatory agencies to protect the San Francisco Bay, the Pacific Ocean, and the communities it serves.

For visual learners out there, the SFPUC partnered with the California Academy of Sciences on developing “The Story of Poo” to shows how the City’s sewer system works.