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:
Mosquito Control – issued to mosquito control districts for the control of adult and larval mosquitoes
Noxious Weed Control Permit – for the control of noxious and quarantine list weeds along lake and river shorelines, in rivers, wetlands, and estuaries. Coverage is issued to the State Department of Agriculture.