children learning about watersheds and pollution prevention

KEEPING OUR WATERWAYS CLEAN

Conserving our water resources.

Keeping Our Waterways Clean

Stormwater pollution in San Mateo County is an issue that affects creeks, San Francisco Bay, and the Pacific Ocean. Stormwater is runoff from rain, snowmelt, and irrigation that flows over surfaces like roads and sidewalks without soaking into the ground. Stormwater runoff in San Mateo County enters storm drains and travels underground to local creeks and waterways before eventually reaching the San Francisco Bay or the Pacific Ocean—without being treated at a water treatment facility.

As a result, pollutants such as trash, oil, soaps, pet waste, sewage, automotive fluids, construction materials, paint, sediment, and even food waste can contaminate our waterways, harming both aquatic and human life. To protect water quality, it is strictly prohibited to dump, spill, or discharge these pollutants into the storm drain system. Preventing stormwater pollution is a shared responsibility, and everyone can take part.

How to Prevent Stormwater Pollution

Together we can keep our waterways clean.

Owner picking up dog poop on grass with pet waste disposal bag

Pick Up After Pets

Stop poo-llution by making sure to carry pet waste bags on walks and using them to bag pet waste and dispose the waste into a garbage bin. Pet waste can carry bacteria that is harmful to both humans and other animals. This small act helps keep our public spaces clean and protects waterways.

Pick Up Trash

Make sure trash, recycling, compost, and yard waste are properly secured in bins and disposed of correctly to prevent litter from washing into storm drains. Simple things like making sure there is a lid on bins when put out for pick up, or bagging trash securely can go a long way in keeping our road and water ways trash free.

woman buying laundry detergent and reading the label

Pick Eco-Friendly Products

Consider choosing products with minimal packaging or those that use recycled materials to further decrease environmental impact. Additionally, support brands that prioritize sustainability in their manufacturing processes. By making these conscious choices, you contribute to a healthier planet and encourage industries to adopt more eco-friendly practices

trailer with litter and debris with proper tarp covering

Tarp Your Load

Litter and debris placed in truck beds can end up in local waterways and harm wildlife especially if not properly covered and secured. Not only does this practice help protect the environment, but it also ensures safety for other drivers. Loose debris can become hazardous projectiles.

Learn More About Keeping our Waterways Clean

Everyone can help prevent stormwater pollution.

two people talking while walking a dog on leash in a park

Pet Waste

Pets bring joy and companionship, but their waste can create environmental challenges when not managed properly.

Green Infrastructure

Green infrastructure offers an effective approach to managing stormwater pollution by leveraging natural elements such as natural vegetation and soils to mimic natural water management processes.

Water Quality Projects

The Sustainability Department plays a key role in coordinating water quality improvement projects across other County Departments and municipalities.

storm drain during rainstorm safeguards water resources

Stormwater Ordinance

The County of San Mateo Stormwater Ordinance is a local regulation for the unincorporated county area that implements a state-mandated program to protect and enhance our waterways.

San Mateo County Watersheds

A watershed is the area of land where all the water drains into a particular creek, bay, or ocean. Everyone lives in a watershed, and activities in this area can impact water and habitat quality for wildlife and people. Pollution in one part of a watershed can affect areas downstream. Human actions—whether positive or negative—can influence the health of a watershed, including the water quality, wildlife, vegetation, and overall quality of life. In San Mateo County, most stormwater runoff eventually travels from storm drains and creeks and flows into the San Francisco Bay or the Pacific Ocean.

Use this map to find out what watershed your home, office, or school is in.

Integrated Pest Management Policy

Integrated Pest Management (IPM) is an ecosystem-based approach aimed at long-term pest prevention through techniques such as biological controls, mechanical controls, cultural controls, and reduced-risk chemicals. Under the San Mateo Countywide Water Pollution Prevention Program Model Integrated Pest Management (IPM) Policy (PDF), pesticides are applied only when necessary with a focus on targeting specific pests while minimizing risks to human health and the environment. This strategy applies to various County-managed properties, including parks, roadsides, and municipal buildings.

The Latest News & Events

Jun
27

Compost Workshop

Learn how easy and fun it is to recycle your fruit and vegetable scraps, leaves, and plant cuttings into compost in these free workshops! These workshops teach composting options suitable for those with or without a backyard. Apartment dwellers welcome! Compost provides valuable nutrients for your garden soil, helps retain moisture, which saves water, prevents erosion, loosens clay and compacted soils for better drainage, and suppresses weeds. It is rewarding to know you are turning what some consider waste into precious organic material for your garden.

Discounts and rebates for backyard compost and worm compost bins will be distributed to San Mateo County residents!

COMPOST WORKSHOP

Date: June 27, 2026
Time: 10:00 AM – 12:00 PM
Location: Foster City Community Garden
Register here.

LEARN MORE

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Keeping Our Waterways Clean

How to Prevent Stormwater Pollution