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Pesticides and Integrated Pest Management

This page provides a basic overview of pesticides and integrated pest management for local governments in Washington State, including relevant laws, local examples, and helpful resources.


A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest. Pests can be insects, mice and other animals, unwanted plants (weeds), fungi, or microorganisms like bacteria and viruses.

Pesticides can be harmful to humans and the environment, so the federal and state governments regulate their use and some local governments have adopted policies to reduce pesticide use.

What is a Pesticide?

Though often misunderstood to refer only to insecticides, the term "pesticide" also applies to herbicides, fungicides, and various other substances used to control pests. According to the U.S. Environmental Protection Agency (EPA):

A pesticide is any substance or mixture of substances intended for:

  • Preventing, destroying, repelling, or mitigating any pest
  • Use as a plant regulator, defoliant, or desiccant
  • Use as a nitrogen stabilizer

RCW 15.58.030(31) states that “pesticides” includes, but is not limited to:

  • Any substance or mixture of substances intended to prevent, destroy, control, repel, or mitigate any insect, rodent, snail, slug, fungus, weed, and any other form of plant or animal life or virus, except virus on or in a living person or other animal which is normally considered to be a pest or which the director may declare to be a pest;
  • Any substance or mixture of substances intended to be used as a plant regulator, defoliant or desiccant; and
  • Any spray adjuvant.

A similar definition is provided in RCW 17.21.020(36).

What is Integrated Pest Management?

Integrated pest management refers to the process of minimizing pests using a variety of strategies, with the goal of reducing the use of chemical pesticides and using less-toxic pesticides whenever possible. Ch. 17.15 RCW requires designated state agencies to use integrated pest management, and many local governments have adopted their own IPM policies.

The National Marine Fisheries Service (NMFS) has cited Portland, Oregon's Parks Integrated Pest Management Program as a model. See Portland Parks and Recreation Invasive Plant & Pest Management.

For more information, see:

State and Local Pesticide Regulation

The use of pesticides under state law is governed by the Washington Pesticide Application Act, chapter 17.21 RCW, which authorizes the state Department of Agriculture to regulate pesticide application and use. This chapter preempts cities and counties from regulating pesticide application and use. However, first class cities with a population of 100,000 or more, and the counties in which they are located, can regulate structural pest control operators, exterminators, and fumigators (RCW 17.21.305).

The Washington Pesticide Control Act, chapter 15.58 RCW, authorizes the Department of Agriculture to regulate formulation, distribution, storage, and disposal of pesticides. This chapter does not preempt cities and counties from regulating these activities, so long as the local regulations do not conflict with state law. See AGO 1993 No. 5.

In addition, the state Department of Ecology regulates the use of aquatic pesticides under chapter 90.48 RCW. For more information, see the Department of Ecology’s webpage on Aquatic Pesticide Permits.

Also see:

Use of Pesticides by Local Governments

State Permits

Government employees who apply any "restricted use pesticide" (defined in WAC 16-228-1231) or any pesticide by means of an "apparatus" (defined in RCW 17.21.020(4)), are required to have a public operator license issued by the state Department of Agriculture (RCW 17.21.220). The license must be renewed annually, and the bearer must take continuing education training courses over each five-year period to maintain certification (RCW 17.21.128RCW 17.21.132).

A public operator license is not necessary for off-the-shelf products applied by hand.

For more information on public operator licenses, see the following pages:


Local governments can be held liable for application of any pesticide that damages private property (RCW 17.21.220(4)).

Safe Handling and Disposal of Pesticides

Pesticides can potentially be hazardous to human health and the environment, and they should be handled and disposed of properly. For more information, see:

Use at Schools or Licensed Daycares

In addition, public schools and licensed daycares in Washington must notify parents and employees of pesticide use. For more information, see:

Examples of Local Pesticide Policies and Plans

Integrated Pest Management Plans

Below are some examples of cities and counties that have adopted integrated pest management policies.

Banning Certain Pesticides

Below are examples of local policies banning the use of all or certain pesticides.

Webpages and Supporting Resources

Below are examples of other local government pesticide resources, such as websites explaining pesticide use and regulations to the public.

Recommended Resources

Last Modified: April 02, 2021