How Stormwater Pollution is Affecting San Diego – Project Clean Water

How Stormwater Pollution is Affecting San Diego

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Stormwater pollution is one of the most persistent threats to San Diego’s water quality. Stormwater is untreated – meaning that it travels directly into our rivers, lakes, and the ocean, along with any pollutants it may pick up along the way. The facts are relatively simple – but what are some of the actual effects that stormwater pollution has on San Diego?

Impacts on Wildlife

Did you know that San Diego is one of the most biodiverse areas in the world? Our region is home to an incredible population of wildlife from tiny, tide pool dwelling invertebrates to large animals like the California Sea Lion or Mountain Lion. Stormwater pollution caused by soaps from washing cars, fertilizers, herbicides, and pesticides from gardening, and trash left behind as litter can introduce an array of threats to their natural environments – including harmful chemicals, choking hazards, and objects like mask strings that could potentially injure wildlife.

Increased Flooding

Stormwater pollution caused by yard debris like grass or leaves, trash, and other litter can block storm drains and water pathways. Clogged storm drains may cause water in our communities to back up, causing increased flooding.

Beach/Waterway Closures

Because stormwater is not treated, the water that flows through our watersheds picks up pollutants on it’s way, which then contaminate our rivers, lakes, beaches, and ocean. If stormwater pollution becomes severe enough, it is only a matter of time until beach and waterway closures occur to protect public health.

Harmful Algae Blooms

Algae blooms often occur in fresh and salt water when excess  “nutrient” chemicals like phosphorous and nitrogen (e.g. chemicals in fertilizers, manure, pet waste, and decomposing green waste) accumulate. These nutrient pollutants are carried into our waterways when rain or over-irrigation washes fertilizers and green waste into storm drains. Algae blooms can dangerously sap oxygen in water and create dead zones, as well as produce toxic chemicals that can make people and animals sick.


Excess runoff can erode banks and beaches far beyond their natural rate. Closer to home, bare areas of soil can wash away when over-irrigated or when it rains. Plant native ground cover to prevent sediment from washing off your property and clogging storm drains and downstream waterways.

While all of the above is a cause for concern, there are many simple steps you can take to protect our clean water and healthy communities. Here are a few:

  1. Prevent runoff: taking steps to reduce irrigation runoff and over-irrigation will help to reduce the amount of untreated stormwater entering our waterways. Fixing broken or misaligned sprinklers and reducing watering time are a great start.
  2. Source reduction: Help decrease trash and pet waste that enter our waterways by picking up litter and pet waste, using less fertilizers and pesticides, and repairing leaking vehicles.
  3. Capture water: Use rain barrels to capture and reuse runoff. Install permeable pavement and redirect gutters and downspouts to a permeable landscape instead of allowing it to run into storm drains.

 Get more tips on how you can help here.


Ready to get on board with Project Clean Water? If you haven’t already, take our 52 Ways to Love Your Water Pledge and join us in taking simple, weekly actions to reduce stormwater pollution.

52 Ways to love water