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Only Rain Down the Drain

kids holding a car washing sign

Save and keep local waters clean!
See our Guide to Car Washing in San Francisco.

Most of San Francisco has a combined sewer system that collects and treats both wastewater from homes and businesses and stormwater that falls on the city's streets and into the catch basins. Combined wastewater and stormwater goes to the treatment plant where it is fully treated prior to being discharged into the Pacific Ocean or San Francisco Bay. 

However, parts of the city are served by separate sewer systems, where stormwater flows into storm drains and into a different set of pipes than wastewater, and goes directly into the Bay and Ocean with minimal treatment. Separate storm sewers are located on the outer edges of the city, including Ocean Beach, Lake Merced, and Mission Bay. In these parts of the city it is especially important to keep pollutants out of the storm drains.


Keep Pollutants Out of the Bay and Ocean and Minimize Flooding

Pollutants such as trash, pet waste, pesticides, and motor oil may end up in our storm drains. Here are several ways you can prevent pollution in our storm drains:

  1. Stormwater and Pollution Prevention: learn what you can do to help prevent pollution.
  2. Use less-toxic gardening products in your garden.
  3. Properly dispose of pesticides that remove lice, ticks, fleas, ants, and any other outdoor pest.
  4. Dispose of household chemicals at a recycling center or household hazardous waste facility.
  5. Always pick up your pet’s waste and throw the bagged waste in the trash.
  6. Never litter, dispose of trash properly.
  7. Remove some of the concrete in your front “yard” and plant a tree or make a rain garden.
  8. Ride a bike or take public transportation instead of driving alone to work can reduce the amount of harmful car exhaust pollutants from the street.
  9. Attend a Coastal Clean-Up Day event.
  10. Bring your car to a professional car washing facility since they capture all of the soapy runoff that may otherwise pollute local waters.
  11. When you wash your car at home, motor oil and other pollutants can get washed down the street and enter the City’s storm drains, which lead to the San Francisco Bay or Pacific Ocean. Please review the Guide to Washing a Car in SF for useful tips and hints for an environmentally friendly way to wash your car at home.
  12. Sign up on Adopt a Drain SF and pledge to keep a catch basin or storm drain near you free of leaves, debris and pollution.


Adopt a Drain!

Catch basins are the semi-circular grids that you see at almost every street corner throughout San Francisco. There are over 25,000 catch basins in the City.

They are the main entryway for stormwater and street runoff into our combined sewer system for treatment. Storm drains are similar, but drain directly to the Bay and Ocean with minimal treatment.

Adopt A Drain SF

Adopt a drain today and help us maintain them clean and ready for rain!  

Clean Catch Basin - clean environment Dirty Catch Basin - polluted waterways
A clean catch basin means a clean environment. A dirty catch basin means polluted and clogged sewers.

For Food Trucks

Greywater and fats, oil, and grease (FOG) from your food trucks should not enter storm drains and catch basins. There are lots of ways you can help prevent pollution when operating. Find out how, and learn more interesting facts here

PP Food Trucks

SF 311 logo

To report clogged catch basins, call San Francisco's 3-1-1 or go to

Litter, leaves and debris can clog catch basins and storm drains, causing neighborhood flooding and pollution of our waterways. Urban stormwater runoff is the leading cause of water pollution in California.


Last updated: 6/23/2020 2:22:17 PM