top of page
  • Writer's pictureJen

Removing Aquatic Weeds in Washington State

Eurasian watermilfoil
Eurasian Watermilfoil (Image from

I want to clear the seaweed from my pond so my kids can go swimming. How can I do that in Washington?

That's easy. There are several ways to get rid of aquatic weeds, and using mechanical tools like a rake and a weed knife can take care of it without a lot of work and a scuba suit. Better yet, cutting them out is a lot safer than using weed killers that harm all the plants and might poison other organisms like fish, or even people.

Are there any invasive plants that I should be aware of?

There are several. Some are submerged (live entirely underwater), others float or live half in, half out, and some live on the shore.

It's best to take care of them early and often, so if you're starting to show signs of them appearing it's time to take action today.

The worst offenders are:


  • Eurasian watermilfoil

  • Brazilian Elodea

  • Curly-leaf pondweed

  • Grass-leaved saggitaria


  • Fragrant Waterlily

  • European frog-bit


  • Yellow-flag iris

  • Japanese knotweed

  • Purple loosestrife

  • Garden loosestrife

  • Grass-leaved arrowhead

What do I need to know about the law before I start cutting?

We encounter people with misconceptions of questions about the law out at trade shows all the time, so we sifted through the various laws and departments to make it easier for you. Laws can change and we’ll update these guides as quickly as possible. As always, you should contact your local office of the Department of Environmental Quality or Department of Natural Resources for advice on your exact situation.

Note: AquaticWeedTools is not a law firm. As such, AquaticWeedTools does not provide legal advice. The material in this guide does not constitute legal advice nor does contributing to the guide or communicating with AquaticWeedTools or other contributors about the guide create an attorney-client relationship.

The State of Washington lets you do a lot to clear up the weeds in your ponds or lake without a permit if it’s your land and you’re using mechanical tools. (Or your bare hands if you're clearing Eurasian Milfoil!)

First of all, if you're dealing with an invasive weed breakout and have questions about what it is exactly, you reach out the Washington Department of Fish and Wildlife for assistance identifying it.

They put out a pamphlet with updated rules in 2015 if you want more details. Since you need a licence to use weed killer in a lake in Washington, they recommend hand removal or using tools like a weed knife and rake for all weeds except Eurasian Mill Foil since rakes can spread the infestation. Contact the Washington DFW for advice identifying and removing Mill Foil.

Mechanical removal requires no special approval. We (and they) recommend reading this pamphlet for advice on the best time of year to control weeds in your area of the state. It's very comprehensive!

Anyway, you don't need permits if you keep it simple. You can do things like have herbicides applied by a licensed professional or use dredgers or more complicated mechanical tools but they all require a Hydraulic Project Approval from the state which takes time and money. They're the best option for an infestation wildly out of control.

What tools should I use to clear out the weeds around my dock?

The Aquatic Weed Rake from Prime Waters Manufacturing is designed to clear pesky weeds out with minimal effort, and safe enough to be used by any contractor or anyone in the family.

For Washington weeds, we recommend using the Dock Weed Rake and Dock Weed Knife, and the Surf/Sand Rake to remove them once you're done cutting them down. Simply dispose of them like you would yard debris, compost them or there are companies you can hire to haul them away.

Having a clear pond all summer has never been so easy and safe for your family. If you have any questions at all, reach out to us. Our experts are ready to help!

Sources and Links

1,228 views0 comments


bottom of page