Aquatic Plant & Algae Management General Permit

We issue the Aquatic Plant and Algae Management (APAM) General Permit to allow the management of in-water and shoreline (roadsides, dikes/levees, and ditch banks) noxious weeds, native nuisance plants, and algae.

This is a combined National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit that allows the use of a specific list of aquatic-labeled herbicides, algaecides, biological water clarifiers, adjuvants, marker dyes, shading products, and phosphorus sequestration products into the fresh waters of Washington.

The current permit went into effect on April 21, 2021, and expires on March 21, 2026.

Join our listserv to receive email updates about this permit.

We've updated our sign template to use more icons to help applicators warn people about any restrictions. 

Current permit documents

Historic Documents

Additional documents

WDFW Restricted Areas for Aquatic Pesticides Map Tool (Treatment Timing Windows)

Map shows specific locations where use of aquatic herbicides is subject to different timing restrictions to protect fish and other priority species. Click image to go to WDFW's map.