Washington Friends of Farms & Forests

We Help Washington Grow

National Pollutant Discharge Elimination System (NPDES) Permits

In Washington State, National Pollutant Discharge Elimination System (NPDES) permits are required for any application of pesticides in or adjacent to water including lakes, rivers, estuaries, and irrigation canals. This includes wetlands with standing water. If the ground is dry and residues will dissipate before the next rain, no permit is needed.


The Washington Department of Ecology (Ecology) developed these permits in 2001-2002 in response to a Ninth Circuit Court decision, Talent Irrigation District v Headwaters, Inc. Ecology has delegated authority from EPA to enforce the Clean Water Act in Washington State.


The following general NPDES Permits have been issued:



Two individual Permits were developed for unique circumstances:


  • Fish Management – issued to the Washington State Department of Fish and Wildlife for the use of rotenone in lakes.
  • Invasive Moth Control – issued to the Washington State Department of Agriculture for control of various moth species, including gypsy moth.

Click here for a list of pesticides allowed under each permit: http://www.ecy.wa.gov/programs/wq/pesticides/regpesticides.html