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Newsletter – October 2018

Reminder: Scoping Comment Period for the Underground Flow Equalization System Project Closes Oct. 22

The City is preparing an Environmental Impact Report (EIR) for the proposed Underground Flow Equalization System Project (formerly known as the In-System Storage Project). Public comments regarding how the proposed project may affect the environment are being accepted through October 22, 2018.

This project is part of the city’s 10-year program to improve and repair the aging sewer collection and treatment system.  The approximately 5-million-gallon underground holding structure is proposed to be located in the eastern portion of the San Mateo County Event Center parking lot. The system will serve as a temporary holding area for the mixture of sewage and excess rainwater that commonly overwhelms the sewer system capacity during heavy rains, which often results in overflows at the wastewater treatment plant and at locations around the city, such as manholes. This will allow the wastewater treatment plant to “catch up” with the high flows. The design of the project is sixty percent complete, and more details about construction schedule and cost will be released as they become available.

The public scoping period began on September 7, 2018, and a public meeting was held on October 2.  Comments must be submitted by October 22, 2018 to be considered. Written comments should be addressed to: City of San Mateo, Clean Water Program, Attn: Heather Waldrop, 330 W. 20th Ave, San Mateo, CA 94403, or emailed to

The public will be invited to review and comment on the Draft EIR when it is released, and will be notified of additional opportunities for input as the project progresses through the CEQA process.

Prepare Now for Rainy Weather!

The rainy season is nearly upon us! While the Clean Water Program is doing its part to upgrade the wastewater collection and treatment system for optimum efficiency, property owners in San Mateo can help these efforts by being proactive now and throughout the year.

One of the most effective actions you can take to keep sewer lines clear is to refrain from flushing anything besides toilet paper. Items like the not-so-flushable wipe, facial tissues, paper towels, feminine products, and dental floss may pass through the plumbing in your home, but can lead to blockages and failure in the main collection and treatment system.

Another tip to keep your sewer from clogging is to put as little fat, oil, and grease down the drain as possible. These accumulate in the plumbing and sewer lines, causing blockages and leading to equipment failures. 

Inspect any drainage system on your property (foundation drain, yard, driveway, sump pump, etc.) for potential blockages now while the weather is dry, so that any necessary repairs can be made in time for the rains.

While the City’s stormwater system is separate from our sewer system, property owners are also encouraged to keep storm drains clear of leaves, trash, and other debris that might prevent proper drainage and lead to backups and standing water. Consider joining the City’s Adopt-A-Drain program to learn more; tools and materials are available to help!

Please do not attempt to clean storm drains when standing water is present. For immediate attention to clogged storm drains or sanitary sewer lines, please call 650-522-7350. Our Public Works Department will come out to clear the blockage any time of day or night.