About Us

San Mateo County strives to protect stormwater, prevent flooding, and reduce pollution in our creeks, the Bay, and the Ocean. We lead a wide range of activities, including:

Learn more about our programs in our FY 16-17 Annual Report.

Stormwater 101

What is Stormwater?

Stormwater is runoff from rain, snowmelt, and irrigation water that travels over impermeable surfaces like roads, sidewalks, and parking lots and doesn’t soak into the ground. This water enters storm drains and is piped underground where it flows into creeks and streams and eventually into the San Francisco Bay or the Pacific Ocean. Stormwater isn’t treated, so any pollutants left on the ground like trash, oil and dog waste are picked up and deposited into the Bay and Ocean. These pollutants can degrade water quality and harm aquatic and human life.

What is a Watershed?

A watershed is the land that water flows over or through on its way to a creek, delta, bay, or ocean. Everyone lives in a watershed, and everything that happens in the watershed affects water quality and habitat quality for fish, birds and other living things. Pollution in distant parts of a watershed can be washed into storm drains, and cause problems downstream. Human activities can harm or improve the condition of a watershed, including its water quality, its fish and wildlife, its forests and other vegetation, and the quality of life for people who live there. Most of the stormwater runoff in San Mateo County eventually drains into the San Francisco Bay or the Pacific Ocean.

Stormwater Pollution Prevention

Storm Drain Pollution WarningThrough city and county stormwater programs in the Bay Area, the water quality of our local creeks, the Bay, and the Ocean can improve. With improved water quality, the marine ecosystem will become healthier, which will enhance the quality of life for all Bay Area residents.

In San Mateo County, there are several programs aimed to reduce stormwater pollution and manage stormwater quality:

  • The Municipal Regional Permit is issued by the State and requires San Mateo County and its municipalities to enact stormwater pollution prevention measures related to construction activities, industrial sites, new development, trash management, and more. The Office of Sustainability is responsible for overseeing the Municipal Regional Permit.
  • The San Mateo Countywide Water Pollution Prevention Program is a partnership between the City/County Association of Governments, the County of San Mateo, and every incorporated city and town in the county to conduct coordinated stormwater management.

Report Stormwater Pollution

photo of Illegal dumping in canalOnly stormwater is allowed to enter the storm drain system. Potential pollutants and other materials such as washwaters, sewage, automotive fluids, construction materials, paint, sediment, silt, and food wastes are not allowed to enter the storm drain system. Reporting incidents of water pollution problems such as illegal dumping, spills or illicit discharges helps keep our local creeks, San Francisco Bay, and the Pacific Ocean clean.

When should you make a report?

  • When you find dumped waste in or near the storm drain
  • When you notice unusual odors in or near the storm drain
  • When the drainage system has unusually large flows during dry periods
  • When you see someone illegally dumping anything into a storm drain

How can you make a report?

  • For direct discharges to Colma Creek, San Bruno Creek, or San Francisquito Creek: Julie Casagrande,, 650-363-4100
  • In unincorporated areas of San Mateo County: Office of Sustainability,, 1-888-442-2666
  • In cities or towns in San Mateo County, contact the appropriate illicit discharge coordinator from the list found here:

Note: If you are reporting an emergency situation that could result in imminent or substantial danger to the health and safety of persons, call 911.

County Initiatives

Green Infrastructure

Green infrastructure is a great way to prevent stormwater pollution by using vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments. The County’s Green Infrastructure Workplan was approved by the Board of Supervisors in April 2017. The Workplan explains how the County will begin to incorporate green infrastructure into our unincorporated communities. The Workplan outlines strategies ranging from outreach and education, to modification of policies and ordinances.

To learn more about green infrastructure visit the EPA’s Green Infrastructure Basics webpage.

To learn more about incorporating green infrastructure in your new development project visit the County’s Planning and Building page.

Coastside Watershed Protection

Pacifica State Beach and San Pedro Creek

In 2013 the San Francisco Regional Water Quality Control Board (Water Board) found that waters in Pacifica State Beach and San Pedro Creek had high levels of bacteria pollution. The County, the City of Pacifica, and the Water Board worked together to develop a plan to reduce water pollution levels.

For more information on the San Pedro Creek and Pacifica State Beach Bacteria Total Maximum Daily Load (TMDL), visit the San Francisco Bay Regional Water Quality Control Board’s webpage.

San Vicente Creek

In 2016 the Water Board developed a similar plan for the San Vicente Creek watershed. The County is in the beginning stages of implementing the activities as described in the plan. It is especially important to protect San Vicente Creek because it drains to the James V. Fitzgerald Marine Reserve, an area with a wide diversity of marine life.

For more information on the San Vicente Creek and Fitzgerald Marine Reserve Fecal Indicator Bacteria Project, visit the San Francisco Bay Regional Water Quality Control Board’s project page.

How can you help protect San Vicente Creek?

  1. If your home has a septic system, learn more about maintaining your system to prevent water pollution at the County of San Mateo Health System.
  2. Dog owners, fill out the pledge below. Dog waste, even in your backyard, can pollute our water resources. Learn more about the connection between pet waste and the environment at San Mateo Countywide Water Pollution Prevention Program.

Check out the County’s recent efforts in the watershed to tackle pet waste here!

Create your own user feedback survey

Fitzgerald Area of Special Biological Significance Pollution Reduction Program

The James V. Fitzgerald Area of Special Biological Significance (Fitzgerald ASBS) was created in 1969 to protect the mosaic of habitats and tremendous diversity of marine life that exists in this area. The Fitzgerald ASBS is located approximately 7 miles north of Half Moon Bay and extends from 4th Street, Montara south to the Pillar Point breakwater. The Fitzgerald Marine Reserve (Reserve) is located within the boundary of the ASBS.

The Reserve is currently designated as a marine Protected Area and is jointly managed by County Parks and the Department of Fish and Game. A 5.5-mile band of shoreline including the Reserve was designated as an ASBS by the State Water Resources Control Board due to the diversity of habitat. Past studies and monitoring efforts have recorded 164 species, 134 species of algae and marine flora, many bird species, and several mammals including harbor seals, sea lions and sea otters. This is a unique area along the Pacific coast, and is worth protecting.

In June 2011, San Mateo County began working on the Fitzgerald ASBS Pollution Reduction Program (project). The project was led by the Department of Public Works in collaboration with the San Mateo County Resource Conservation District and the San Francisco Estuary Institute. This project was funded in part by a Proposition 84 grant from the State Water Resources Control Board and continued through March 2016. The project involved implementation of targeted stormwater Best Management Practices (BMPs), water quality studies, BMP effectiveness monitoring, and education and outreach. The project’s goal was to improve water quality and protect beneficial uses of the Fitzgerald ASBS and assist in the County’s compliance with ASBS stormwater regulations.

Project information and the final project report are available in our resources section.

For more information, explore the following links:
San Mateo County Planning and Building
San Mateo County Resource Conservation District

Tarp Your Load

Clean water starts with clean streets.  Litter and debris that falls out of truck beds can end up in local waterways and harm wildlife. Check out our educational brochure to learn more about securing your load, and browse the Protect Every Drop website for more tips on how you can help keep our waterways clean.

Get Involved

Check out the volunteer page for upcoming volunteer opportunities.

Check out the Office of Sustainability events calendar for upcoming events and the Flows to Bay events calendar too!

Learn More

We need your help to keep our stormwater clean – it’s a team effort. Learn more about stormwater basics and get all your pollution prevention questions answered at Doing your part is simple!

For questions contact the Office of Sustainability at 1-888-442-2666 or