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


Clean Water Program Neighborhood Meeting, May 2

On May 2, Clean Water Program staff hosted a neighborhood meeting to update residents about upcoming work to upgrade and expand the wastewater treatment plant. The meeting featured a presentation and a Q&A session. The presentation can be viewed here.


Underground Flow Equalization System Project – Extension of Draft EIR Public Comment Period & New Community Meeting

The City of San Mateo has extended the public comment period for the Draft Environmental Impact Report for the Underground Flow Equalization System Project (a proposed solution to lower the risk of sewer overflows during heavy storms).


The comment period will now run through May 31, 2019. Written comments should be addressed to San Mateo Public Works Engineering, 330 W. 20th Ave., San Mateo, CA 94403, Attn: Clean Water Program, or emailed to

**Initial notices included an incorrect email address. If you previously submitted comments to Heather Waldrop, please resubmit them to**

Written comments should be received by 5:00 p.m. on May 31, 2019.

The report is available for public download at here. Hard copies are also available at City Hall, the San Mateo Main Library, and the Hillsdale Branch of the San Mateo Public Library.


Community Meeting at 7:00 pm on May 21

On May 21, the Clean Water Program will host a community meeting about the Underground Flow Equalization System Draft Environmental Impact Report, with time for questions and answers.


The meeting will be held at 7:00 p.m. at the San Mateo County Event Center, Event Pavilion. Enter at 1346 Saratoga Dr. Park near Gate 8, follow signage to Event Pavilion. Parking is complimentary.

Map of San Mateo Event Center


Public Review and Comment Period on Environmental Report Extended

The City prepared a Draft Environmental Impact Report (Draft EIR) to review the potential environmental impacts associated with the Underground Flow Equalization System Project (UFES Project). Prior to preparing the Draft EIR, the City conducted a 40-day public scoping effort to solicit comments on the scope of the EIR. More information about the UFES Project can be found here.


The Draft EIR is now available for public review and comment through May 31, 2019.

A digital copy of the Draft EIR is available for download at the links provided below. Hard copies are available for viewing at the following locations:

  • City Hall, 330 West 20th Avenue
  • San Mateo Main Library, 55 West 3rd Avenue
  • Hillsdale Branch – San Mateo Public Library, 205 W. Hillsdale Boulevard

Please send your comments to:

City of San Mateo Public Works Engineering 330 W. 20th Avenue, San Mateo, CA 94403, Attention: Clean Water Program, or emailed to

If you previously submitted comments to Heather Waldrop, please kindly re-send them to




Upcoming Events


3 Fri
12:00 am
1:00 am
2:00 am
3:00 am
4:00 am
5:00 am
6:00 am
7:00 am
8:00 am
9:00 am
10:00 am
11:00 am
12:00 pm
1:00 pm
2:00 pm
3:00 pm
4:00 pm
5:00 pm
6:00 pm
7:00 pm
8:00 pm
9:00 pm
10:00 pm
11:00 pm