Pests are organisms that occur where they are not wanted and cause damage. Pests include some insects, mice and other animals, unwanted plants (weeds), fungi, and microorganisms such as bacteria and viruses


  • Are substances that are intended to prevent, destroy, repel, or mitigate pests
  • Include insecticides, herbicides, and fungicides
  • Can be substances intended for use as a plant regulator, defoliant, or desiccant

Household products considered pesticides include:

  • Insect repellents for personal use
  • Rat and other rodent poisons
  • Flea and tick sprays, powders, and pet collars
  • Kitchen, laundry, and bath disinfectants and sanitizers
  • Products that kill mold and mildew
  • Some lawn and garden products, such as weed killers
  • Some swimming pool chemicals  

Why should I care?

When pesticides end up in our lakes and streams, they threaten aquatic life and can impact our drinking water quality. All pesticides are toxic at some level, but each type varies in its toxicity. While some pesticides may not be harmful to humans, they may be fatal for fish and aquatic invertebrates.

How do pesticides end up in our lakes and streams?

Pesticides can enter our waterways via stormwater runoff or outdoor water use. Runoff carrying pesticides into our storm drains or directly into lakes and streams may result in serious impacts to fish and wildlife.

What can I do to help?

  • Use environmentally-friendly alternatives to pesticides
  • Use pesticides responsibly and only if necessary
  • Accurately identify the pest
  • Select the most effective pesticide that poses the least risk to human health and the environment
  • Apply pesticides in dry weather, not right before big storm events
  • Never allow pesticides to enter storm drains or creeks