What is Urban Runoff?

Urban runoff is water in urban settings from rain and outdoor water use that drains from roofs, driveways, sidewalks, and other surfaces that doesn't soak into the ground. This water flows into the storm drain system, which is separate from the sanitary sewer system.

What is polluted runoff, and what causes it?

When the water runoff flows over surfaces, it will pick up and carry pollutants it encounters. Many of these pollutants come from waste that we produce or mishandle at our homes. Common runoff pollutants include oil, paint, household cleaning supplies, sediment, pesticides, fertilizers, trash, yard waste, and pet waste.

The everyday activities we do around our businesses, homes, and yards can impact the quality of the runoff that drains into our waterways. Some common examples that can contribute to harmful runoff includes over fertilizing our yards or fertilizing before a heavy rain, not picking up pet waste, and excessive use of pesticides.

Why isn't runoff treated?

It is not feasible to treat all runoff. Varying intensities, from outdoor water use to intense storm events, make it challenging to build a treatment system that can handle all runoff flows.

Why do we need to manage polluted runoff?

Managing runoff helps improve its quality and reduce its volume over time. Unlike sanitary sewer water, runoff flowing into our storm drains doesn’t receive any treatment before entering our waterways and basins, thus delivering any pollutants that it picked up along the way. This contaminates our creeks, irrigation ditches, park-ponds, and potentially our groundwater. In addition, water that doesn’t seep into the ground runs off to downhill areas, which can cause local flooding and stream bank erosion.

How can I help to prevent runoff pollution?

There are many small actions you can take to help prevent runoff. When working around your home or yard, make sure you dispose of products properly, keep items out of storm drains, pick up after your pets, keep yard waste out of the street, and eliminate or minimize the use of fertilizers and pesticides.

Click Here for more pollution prevention tips. See also tips for mobile businesses, tips for construction sites, and tips for restaurants.

Links to Learn More

https://www.casqa.org/programs-initiatives

https://www.waterboards.ca.gov/stormfilm/

https://www.epa.gov/environmental-topics/greener-living

https://www.epa.gov/nps

https://www.epa.gov/npdes/npdes-stormwater-program

https://mywaterway.epa.gov/