National Pollutant Discharge Elimination System (NPDES) Permits for Aquatic Pest Control

The Washington Department of Ecology (Ecology) developed National Pollutant Discharge Elimination System (NPDES) or national discharge permits for the use of aquatic pesticides in lakes, rivers and estuaries in Washington State. Aquatic pesticides include a wide assortment of chemicals that kill, attract, repel or otherwise control the growth of aquatic pests.

Herbicides control plant growth; insecticides control insects and insect relatives; piscicides control fish; and algaecides control algae. Without the pesticide treatments, mosquitoes may threaten people's health and invasive colonies of aquatic plants can harm water quality, reduce fish habitat, block domestic and agricultural water supplies and interfere with boating and swimming.

Ecology developed these permits in response to a recent federal Ninth Circuit District Court decision (Talent Irrigation District versus Headwaters, Inc.). The March 12, 2001, federal court decision affects the application of aquatic pesticides to surface waters in nine western states, including Washington. Traditionally, discharge permits have been issued for industrial discharges, treated effluent from sewage treatment plants and stormwater discharges. The court decision means that national discharge permits will now be required for aquatic pesticide uses. Ecology published a notice of intent to develop NPDES general permits for aquatic pest control in the Washington State Register on July 18, 2001. All permits were issued by June 2002.

For more than 20 years Ecology issued administrative orders for short-term water quality standards' modifications for pesticides applied in or near waterways. The short-term modifications to water quality standards have been issued following human health and environmental impact risk assessments or similar evaluations that supplement the information needed for a pesticide manufacturer to obtain a pesticide label under the U.S. Environmental Protection Agency's FIFRA program. The FIFRA program implements the Federal Insecticide, Fungicide and Rodenticide Act. Now, due to the Ninth Circuit Court decision, applications of pesticides are regulated under a federal Clean Water Act permit as well as FIFRA.

Aquatic Pesticide Permits Page