Runoff - How it Pollutes

Picture of a Ditch

What’s In Your Runoff?(PDF)  Adobe PDF Icon

For more information on how rainfall runoff transports pollutants into our rivers and creeks, take a virtual tour of nonpoint source pollution presented by the San Antonio Water System (SAWS):

SAWS Virtual Classroom – Nonpoint Source Pollution

Frequently Asked Questions

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A: Storm water runoff is anything that is carried by rainwater down into our drainage systems. This includes the water that falls on roofs, lawns, or on paved areas like driveways, sidewalks, parking lots and streets across our city. As this water flows over these surfaces it picks up debris, chemicals, sediments and other pollutants and carries them into our storm sewers.

A: Most runoff pollutants come from chemicals in everyday products and/or bacteria from wastes that we and others dump on the ground. These include:

  • household hazardous waste (HHW) products (indoor pesticides, cleaners, paint, polishers, thinners, cooking oil)
  • automotive fluids (motor oil, transmission fluid, antifreeze, car washing soaps/cleaners)
  • lawn and garden insecticides/herbicides
  • pet or other animal fecal wastes
A: Unlike wastewater from household toilets and sinks, storm water runoff which drains into our storm sewer system is not treated or filtered. Instead, it flows into channels that empty directly into our rivers and creeks. Over time, these pollutants can make the water unsafe and unhealthy for fish, vegetation, wildlife and people.
A: Chemicals from HHW products, automotive care and lawn care products can poison/destroy fish and aquatic plants that live in the rivers and creeks. Animals and people can become sick from eating diseased fish or drinking polluted water while also making the rivers and creeks unsafe for swimming and fishing. These wastes can also cause algae blooms in river/creek water which can decrease oxygen levels and cause fish/plants to suffocate and die off.

About Remember the River

Remember the River is a community campaign focused on nonpoint source pollution prevention outreach and education. The campaign is led by the City of San Antonio.

All campaign education and outreach efforts are conducted in compliance with educational/outreach guidelines established under a TPDES Phase I Municipal Separate Storm Sewer System (MS4) discharge permit regulated by the Texas Commission on Environmental Quality.

Contact Us

Darlene Dorsey 210.207.1011

Email Address:
Email Us

Mailing Address:
P.O. Box 839966
San Antonio, TX 78283-3966