Combined Sewer Systems

San Francisco (like Detroit and New York City) has a combined sewer system.

This means that the stormwater (rainfall) that flows into the storm drains is combined with wastewater from our toilets, sinks and showers.

This combination of stormwater and wastewater can be extreme.  And as the climate changes and storms are measurably increasing in strength, this extreme weather is becoming the norm.  Combined sewer systems are effective during steady rainstorms, but can be easily overwhelmed by extreme precipitation events.

Removing pavement supports the combined sewer system because the stormwater is captured into the soil before it reaches the stormdrain.  Urban gardens support more than just local wildlife.  Urban gardens also restore local watersheds and reduce pressure on the City of San Francisco’s combined sewer system.

The SF Public Utilities Commission has a volunteer program called Adopt a Drain, where residents in SF can adopt a stormdrain near their home and help to keep it free from debris so that stormwater can flow easily in the sewer.  Check out the program and support the SF Bay by being a good neighbor (and remember to bring your broom).

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