Water on the ground goes through the storm drains and out to creeks, streams and the Bay without any filtering or cleaning.
Water that goes down your sinks, toilet and interior drains goes through the sanitary sewer system and is processed to remove most pollutants before it is discharged to the Bay.
The storm drain system carries rainwater and other runoff from roads, parking lots, and roof down spouts directly to local creeks and the Bay, with no treatment.
Along the way to the storm drains, rain and runoff pick up pollutants on the ground and other surfaces. Storm drains collect and convey runoff from most streets in our communities. The storm drains on your street may be stenciled with “No Dumping Flows to Bay” or a similar message. Water flowing through these storm drains is untreated and can carry pollutants to our creeks and streams, which eventually go to San Francisco Bay .
Pollution in our watersheds degrades the environment, harms wildlife habitat, impacts the economy and jobs, causes higher taxes and fees, and ultimately affects the health of humans as well. Pollutants such as motor oil, paint products, pet waste, litter, sediment, and chemicals such as fertilizers and pesticides are washed by rain and over-watered lawns into neighborhood gutters and storm drains.
In day-to-day activities, people can cause some of these pollutants to enter storm drains and creeks without knowing that they are causing harm to the environment. Some pollutants, including pesticides, are found in our creeks at levels high enough to be toxic to aquatic life. Other pollutants, such as mercury, even in relatively small quantities, contaminate certain fish that can be harmful when eaten by small children, pregnant women, or anyone who eats these fish frequently.
Sanitary Sewer System
The sanitary sewer system carries wastewater from sinks, toilets and other indoor drains to local wastewater treatment plants, where processes remove most wastes before the treated water is discharged to the Bay.
However, wastewater treatment plant processes cannot remove all solvents, metals, or synthetic organic chemicals from wastewater, which is why it’s important to dispose of grease and oils, pharmaceuticals and other hazardous materials through an authorized household hazardous waste disposal program.
“Watching Our Watersheds” interactive map layers using Google Earth.
Map the course of storm water from your neighborhood storm drain to the nearest creek, stream or river, all the way to the San Francisco Bay. Explore your Western, Central or Southern Santa Clara County watershed in the past and present.