How and why we regulate the use of pesticides in water

We know you care about the chemicals that may be finding their way into the environment.

person with fishing pole in water

Photo credit: Tristan Hervouet via freeimages

So do we.

That’s why we are focusing on identifying priority toxic chemicals and developing plans to reduce or eliminate their use, or to mitigate their impacts on people and the environment.

Our Water Quality Program has goals to prevent and reduce water pollution and to clean up polluted waters.

To make this work, we engage you to help protect and restore Washington’s lakes, rivers and marine waters.

Clean Water Act protections

When we come to work each day, our Water Quality Program compass is water quality — both in protecting high quality waters and cleaning up polluted waters.

The federal Clean Water Act and the state’s Water Pollution Control Act give us the basic structure of the regulatory programs we use to clean up and protect the health of our waters. And under the act, a water quality permit program is one of our key pollution gatekeepers.

Permits limit pollution

Under our Clean Water Act authorities, a water quality permit is a legal tool that authorizes and limits a pollution discharge.

Sign: Washington State permit required for aquatic pesticides
For example, we permit discharges from large industrial facilities and we permit discharges from wastewater treatment plants. Our Clean Water Act permits allow the discharge of a limited amount of pollution and we recognize that the limited amount of pollution may have impacts. Our permits strive to minimize those impacts.

Protecting the benefits our waters provide

Some people may be surprised to know that both the Clean Water Act and state law allows the use of aquatic pesticides for the purpose of protecting the benefits that our waters provide.

Aquatic pesticides, when used carefully under a water quality permit, can protect water used for domestic, industrial and agricultural purposes, and for livestock, shellfish harvesting, habitat, commerce and navigation, and boating.
Pesticides are used to control:

  • weeds and algae in irrigation systems
  • invasive and noxious weeds in parks and lakes
  • non-native fish

By controlling mosquitoes, we protect public health from diseases. By controlling weeds and algae, we conserve water, protect public safety, and provide a benefit to agricultural production. By controlling noxious weeds, we help protect the environment, public health, and recreation.

Controlling noxious weeds

Twenty years ago, the Legislature clarified that we must allow the use of aquatic pesticides to control noxious weeds when the uses meet our stringent environmental protections.

With strategic and permitted use of aquatic pesticides, we have dramatically reduced infestations of the noxious weed Spartina from more than 9,000 acres in 2003 to around 8 acres today.

Pesticide regulation 101

Pesticides are registered by the U.S. Environmental Protection Agency, which must follow federal pesticide laws. EPA’s lengthy registration process includes health and environmental studies that look at short-term, long-term, and indirect effects.

State law requires that pesticides used in Washington be registered by the state Department of Agriculture. WSDA reviews the EPA registration to determine if there are any state specific concerns, such as endangered species, or drinking water concerns. If there are concerns, WSDA may deny the registration and the pesticide may not be used in Washington. Or they may include it in the restricted-use category, which is the case for all aquatic labeled pesticides. To buy, sell or use aquatic labeled or other restricted use pesticides in Washington, you need to have a license from WSDA.

Pesticide labels

Pesticide labels provide important protections, too. EPA approves the labels and it is illegal to use a pesticide in a way that is inconsistent with the label. However, different manufacturers of the same pesticide may seek approval for different uses – resulting in different labels and therefore different approved uses for the same pesticide.

Before pesticides can be used in or near water, the label needs to specifically state it's OK.

Ecology provides third layer of environmental protection

person jumping into water

Photo credit: Laurivo via freeimages

We provide a third layer of regulation for the use of aquatic pesticides through a water quality permit.
Our state has a strong permitting program to carefully control and manage pesticide use in and around water. The Water Quality program covers the water uses. It does not cover dry land, agricultural uses of pesticides.

Additional protections added by permit

When we consider issuing an aquatic pesticide permit, we evaluate and require environmental protections in addition to EPA and WSDA requirements. Additional conditions may include:

  • when, where, how and the amount of aquatic pesticides can be applied
  • specific monitoring and reporting to evaluate compliance

We also require public notification.

Aquatic pesticide permits contain restrictions, protections

Ecology’s pesticide permits contain a lot of detailed requirements. They set limits to the geographic area where the pesticide may be used. They set restrictions on the pesticides that may be used, opting for the least toxic products that are available. They require public notifications. They limit the timing of pesticide use to protect other plants or animals, such as young salmon. They require post-treatment monitoring to ensure the pesticide was applied correctly. Pesticide applicators must submit reports to us to show that permit requirements were met.

Permit process open to public

Our permitting process is open and transparent to the public. You can review draft permits and give us feedback at different times during our permit development process.  We receive important feedback from you that helps us shape a final permit.

Stay informed

We hope you find this information to be helpful. We invite you to sign up to receive our email notifications about aquatic pesticide permit applications in Washington.