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Pesticides and Water Quality

How Do Pesticides Get into Our Creeks and Rivers?

Pesticides reach creeks and rivers through storm drains and household drains

  • When you apply a pesticide or fertilizer outdoors, some of the material may move to other locations.
  • Storm drains are frequently located in streets. Rain and runoff from garden and lawn irrigation runs down the streets through gutters into the storm drains. In most California cities, the runoff flows through pipes directly into our creeks, rivers, and oceans.
  • Sewers run from drains within the home and carry wastewater from toilets, sinks, and showers to treatment plants.

Drain set

Wastewater treatment plants do not detoxify pesticides

  • While wastewater treatment plants send incoming wastewater through a thorough treatment and disinfectant process before releasing water into the river, they do not actually detoxify pesticides, thus sending residue into our waterways.

How to avoid problems

Drain sewer
Click on image to enlarge

Illustration by Celeste Rusconi

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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