(650) 727-6870 │ Mail: Clean Water Program, City of San Mateo, 330 W. 20th Avenue, San Mateo, CA 94403 info@cleanwaterprogramsanmateo.org


Protecting the Bay for a Sustainable Future


Have you ever wondered where used water (“wastewater”) goes after it leaves your home? Did you know that it eventually reaches the San Francisco Bay? It first travels through a series of sewer pipes and pumps called a sewer collection system and then gets treated at the Wastewater Treatment Plant before it is safe to flow into the Bay.

The Clean Water Program is a comprehensive plan to upgrade the aging wastewater collection and treatment system with advanced infrastructure that will provide reliable services for years to come. The Wastewater Treatment Plant components of the Clean Water Program are a joint effort between the City of San Mateo and City of Foster City/Estero Municipal Improvement District (EMID). The City of Foster City is a partial owner of the Wastewater Treatment Plant. The Goals of the Clean Water Program are to:


Replace aging infrastructure and facilities

Build wet weather sewer system capacity assurance to prevent overflows

Meet current and future regulatory requirements

Align with the City of San Mateo and Foster City's sustainability goals

Read Wastewater: The Basics to learn all about San Mateo’s sewer collection system and Wastewater Treatment Plant!



Latest Info


August 8, 2017, Study Session on the Wastewater Treatment Plant Upgrade and Expansion Project

The study session featured a presentation on the status of the planned upgrade and expansion of the treatment plant on a preliminary basis. The Clean Water Program is in the process of applying for a special use permit for this project from the City, and this session also provided an update on that permitting process.


City Council Selects Location for In-System Storage Facility

San Mateo’s existing wastewater system capacity is insufficient to address the wet weather flows that occur in the winter months and lead to sanitary sewer overflows (SSOs). To address this issue, a comprehensive approach to improve capacity involving an underground, in-system storage facility upstream of the WWTP is planned.

On July 17, 2017, the City Council selected the San Mateo County Event Center for the location of the underground storage facility. The Event Center is near where the most SSOs have historically occurred, near the intersection of S. Delaware Street and 25th Ave. Project. The northeast corner of the property, where the RV Storage Lot is located, will be used for the facility.

This storage facility will be capable of temporarily storing approximately 5 million gallons of wastewater during heavy rains. During these conditions, flows will divert from the sewer pipes to the storage facility to prevent overflows from occurring. After a storm subsides, and generally within 24 hours, wastewater in the facility will be pumped back into the collection system pipes and conveyed to the wastewater treatment plant.



Upcoming Events


Neighborhood Meetings for Residents of the Marina Lagoon and the Southern Portion of the Shoreview Parkside Neighborhoods @ Parkside Elementary School, LGI Room
Oct 17 @ 6:30 pm – 8:30 pm

Neighborhood condition assessment mapThe City of San Mateo’s Clean Water Program will hold two informational meetings about upcoming assessments of the sewer system in the Marina Lagoon and the southern portion of the Shoreview Parkside neighborhoods (see map area below). The meetings will be on October 12 and October 17 from 6:30-8:30 p.m. at Parkside Elementary School.

The assessment work is planned for November 2017 through March 2018, and will include a variety of inspections and tests to determine how best to fix aging or damaged lines. For some of these assessments, the City must obtain homeowners’ permission for workers to enter the property. At the neighborhood meetings, residents will be able to determine the specific activities that may be planned for their property, and if a Right-of-Entry form is required. Residents will also have the opportunity to fill out Right-of-Entry forms at the neighborhood meetings.

These meetings will provide details about the locations and types of work that will be focused on sewer lines, sewer manholes, and storm drain lines. General information about the Clean Water Program will also be presented.

These assessments are a vital element of the Clean Water Program, which is upgrading and repairing the City’s aging sewer collection and treatment system. As part of this program, several sewer projects are planned to improve service and comply with regulatory requirements to protect public health and the environment for years to come.

Meetings will start promptly at 6:30 p.m. with a formal presentation and time for questions, followed by an open house with information stations. The same material will be covered at each meeting; there is no need to attend both. If you have questions about the upcoming meetings or the planned testing, please call 650.727.6870 or email Info@CleanWaterProgramSanMateo.org.

Meeting location map