Storm & Flood Preparedness

​El Niño and King Tides: What to Know This Winter​
On September 21, 2026, Governor Newsom proclaimed a statewide State of Emergency for El Niño preparedness. It directs state agencies to prepare, stage resources, and speed up permitting. It brings no local funding and makes no finding or directive toward San Mateo County.

Learn more about what to expect, what the County and City are doing, and how you can prepare.

Sandbag Corp Yard public Opens in new window

In 2023, voters passed the Community Flood and Storm Protection Fee, which provides a reliable funding source for maintaining and improving the City’s aging stormwater system. City Council subsequently ratified and enacted the Fee in 2024, and the Department of Public Works will be using the funding for long-deferred maintenance and improvement activities. To learn more about the City's upcoming stormwater capital improvement needs, visit our Storm Drain Master Plan webpage.

The City is taking proactive steps to prepare for future rainy seasons, and we encourage residents to do the same.

  1. Be Prepared
  2. Resources & Recovery Information

Please do not call 9-1-1 unless it is an emergency. 

We respond to many calls throughout our community and ask for your patience as we must prioritize how we respond. Please note the City does not manage private property, and private property owners are responsible for maintaining their own property including clearing downed trees.

To report flooding on public property, please call (650) 522-7300 (Public Works). 

Important Phone Numbers

  • Report Flooding, Clogged Drain, or a Sewer Overflow on Public Property: Call (650) 522-7300 (Public Works). 
  • Report Downed Trees: Call (650) 522-7420 (Tree Desk).
  • Report Other Non-emergency Issues: Call (650) 522-7700 (Police Department Non-Emergency Dispatch). 
  • Report Downed Powerline: Call 911.

Please DO NOT call 911 to report flooded roadways and clogged drains. It is important that we keep 911 telephone lines clear for life-threatening emergencies.

Flooded Homes & County Health
San Mateo County Public Health has expanded health and safety guidelines for residents with flooded homes.

Sandbags Available to San Mateo Residents

Sandbag stations are open 24/7 between October 1st and April 30th.

Our self-serve sandbag stations are open to City of San Mateo residents during the wet weather season.

Visit our sandbag web page for more information & locations

Sandbag Rules

  • MAXIMUM 10 bags per vehicle
  • MUST be a San Mateo resident or Property Owner (be prepared to show proof of residency/ownership)
  • BRING your own shovel & heavy-duty trash bags - Sand and bags will be provided while supplies last - bring your own heavy-duty trash bags in case bags run out.
  • MUST be able to fill the bags yourself (these are self-serve locations)

If you are unable to fill sandbags yourself due to a physical limitation or disability, you may arrange to pick up pre-filled sandbags from the City Corporation Yard during regular business hours, 7:00 a.m. to 3:00 p.m., Monday through Friday, by calling 650-522-7297. Field Maintenance staff will assist with loading the pre-filled sandbags into your vehicle.


How the City is Preparing & Responding

  • Leading up to and through the wet weather season, teams are out re-clearing storm water catch basins and trash racks throughout the city
  • In areas more prone to flooding, for safety reasons we may proactively close roads and provide detours
  • Testing stormwater pump stations and planning for operational needs throughout the storm
  • Preparing for additional staffing to assist during intense storms 
  • Marina Lagoon will be held at lower operating levels and may be staffed 24/7 during extreme storm events
  • Arborists monitor public trees
  • We coordinate with the County and neighboring cities
  • We monitor areas with a history of flooding for storm conditions. Read more about these flood-vulnerable areas that are part of the FEMA Flood Zone.


Historical Flooding Public Comment Map
Help Shape the Future of Stormwater Management!
Have you experienced flooding in your neighborhood? The City of San Mateo has launched an interactive historical flooding public comment map where residents can share past flooding experiences.

How to Share Your Feedback
The map allows residents to submit location-based comments, including the type of flooding observed, the date of occurrence, and any additional details. Photos and videos are recommend to be uploaded with comments. This tool is available in English and Spanish.

Access the Public Comment Map:

Why Your Participation Matters
Resident input is essential for validating existing storm drain data and identifying areas where improvements may be needed. Resident input will help staff better understand local flooding issues and prioritize future storm drain infrastructure projects. Your support in adding comments to this tool will help ensure the City is aware of real-world conditions and community needs. Staff will reach out for additional details if needed.