Laguna Street Outfall Rehabilitation Project

A program-wide assessment was performed of outfall structures through the Collections System Reliability Program, which is focused on maintaining the operational reliability of our collection system. Based on video inspections and physical studies by a specialized consultant, the need to rehabilitate the Laguna Street outfall structure was identified due to its age, the importance of the structure, and the sensitivity of the receiving water body. Other factors included structural conditions and compliance with permit requirements.

Project Activities

The Laguna Street outfall rehabilitation will include the following activities: concrete spalling and crack repair, rehabilitation of the existing discharge pipe with carbon fiber wrap or similar material, repair to the baffles, and repair of riprap around the discharge pipe. The work will not impact the discharge capability or any sewer operations.

What is a Combined Sewer Discharge?

San Francisco is the only coastal city in California with a combined sewer system that collects and treats both sewage and stormwater in the same network of pipes and treatment facilities. This combined system means that San Francisco treats stormwater runoff when other coastal cities in California would have stormwater – and the debris and pollutants it picks up – flow untreated into water bodies.

In San Francisco, the debris and pollutants in stormwater runoff are treated to the same high standards that the SFPUC uses to treat sewage from buildings before being discharged into San Francisco Bay or the Pacific Ocean. However, during intense storms the system can reach capacity. When this occurs, it is necessary to discharge partially treated wastewater through outfalls around the City. This combined stormwater and wastewater discharge is more than 90% stormwater. It also receives partial treatment – the equivalent of primary treatment at one of our wastewater treatment plants – before it is discharged. This is known as a combined sewer discharge.

These discharge events are monitored and reported in a timely manner to maintain compliance with all regulatory and permitting agencies. Under the Sewer System Improvement Program, projects such as Baker Beach Green Streets are being constructed to further reduce storm-related discharges. Visit the Beach Water Quality Monitoring Program for more information on storm-related discharges and water quality at beaches.

About the Sewer System Improvement Program

The San Francisco Public Utilities Commission recently launched the Sewer System Improvement Program, a citywide investment to upgrade our aging sewer system and provide a more reliable, sustainable, and seismically safe system now and for future generations.