Aquatic Plant & Algae Management General Permit

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

This s 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 inactivation products into the freshwaters of Washington.

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Permit documents

Permit Reissuance

The current APAM permit expires on March 31, 2021. We're working to develop a new draft APAM permit. Once this draft is complete, we'll begin a public involvement process that includes a public comment period and at least one formal public hearing.

Changes to the permit that we're considering include:

  • Reorganizing and clarifying requirements.
  • Updating requirements based on rule changes or court decisions.
  • Adding language to address repeated questions from the public or permittees from the current permit cycle.
  • Changing the shoreline posting signs for better clarity and understandability by all waterbody users.
  • Other potential issues that may be identified through informal listening sessions.

At this time, Ecology is not considering adding any new active ingredients to this permit.


Fall 2020: Formal public process (public comment and formal hearing) on the draft permit
February 2021: Decision on reissuance
March 2021: Current permit expires

Modifications to the 2016 Permit

We modified the 2016 permit to allow the use of additional tools to control aquatic plants, algae, and noxious weeds. These tools include:

• Three herbicides.
• One algaecide.
• Two phosphorous inactivation products.
• Adjuvants registered by the Washington State Department of Agriculture (WSDA).

We accepted comments on the modified permit documents from Nov. 7, 2018 until Dec. 21, 2018. We held two public workshops and hearings on Dec. 10, 2018. We published a Response to Comments as an appendix to the fact sheet to address comments submitted during this period.

Para obtener más información acerca del permiso general modificado, comuníquese con James Hovis al 360-407-6588.

Additional documents