Rainwater, once it hits the ground, picks up pollutants and carries them to our local water bodies (such as the Bay, ocean or local lakes), either directly or after passing through our wastewater treatment plants.  According to the State Water Resources Control Board, urban storm water runoff is the leading cause of water pollution in California.  The good news is that San Francisco residents and business owners can choose to make a difference everyday through their actions to keep potentially harmful contaminants off of our streets and out of our drains.

Some of the most common storm water contaminants are:

• motor oil and grease (from leaking cars)
• pesticide residue (from chemicals used in your garden)
• pet waste (a source of bacteria and excess nutrients which are harmful to aquatic life)
• paint and household chemicals
• litter and trash
• soil, leaves and grass clippings (another source of excess nutrients)

Pollutants that go down street storm drains can have many negative impacts on our local waters:

• They can poison fish and other aquatic life
• They endanger recreational uses (such as swimming, boating, beaches)
• Sediment and pollutants can hinder the growth of aquatic plant life
• Excess nutrients can cause algae blooms that then decompose and remove oxygen that aquatic life needs to survive - even biodegradable products are problematic
• Solid contaminants (litter, sediment, etc) contribute to clogs in San Francisco's combined sewer and storm system - contributing to system overflows during heavy rains.

San Francisco has a combined storm sewer system - this means that most of our 25,000 street drains are connected to a wastewater plant, where storm water is treated before being discharged to the Bay or the Pacific Ocean.  However, some 2,000 or so street drains do flow directly to local water bodies, such as the San Francisco Bay, Pacific Ocean or local lakes.  Even those street drains that flow to our treatment plants need to be kept contaminant-free because these wastewater treatment facilities were not designed to treat toxic pollutants.

You Are the Solution to Storm Water Pollution!

Everyone - including you -- lives in a "watershed."  A watershed is an area of land that drains to a particular body of water, such as the bay, ocean, river or lake.  Remember: Any actions you take that leave solid or liquid contaminants on the ground can cause storm water pollution.

Get Informed! Learn about San Francisco's Only Rain Down the Drain! educational campaign and the steps you can take to make a difference. Order free home, care and garden pollution prevention guides from the San Francisco Public Utilities Commission.  For copies of Fix It!, Grow It!, Clean It!, and Control It!, call (415)695-7310 or go to http://www.sfwater.org/CleanBay Visit www.ourwaterourworld.orgfor fact sheets and to find retailer that carry less-toxic garden and lawn-care products. Go to www.epa.gov/weatherchannel/for more information and resources on what you can to do prevent storm water pollution. Order the free business guide - Only Rain Down the Drain: Storm Water Pollution Prevention Tips  for Commercial and Industrial Businesses by calling (415)695-7310 or go to  http://www.sfwater.org/CleanBay Learn about the San Francisco Storm Water Management Plan, which has specific programs to target areas of the City where street drains flow directly to open water bodies (i.e., the Bay, ocean or local lakes)