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This page provides an overview of wetlands protection for local governments in Washington State, including relevant laws, examples of local ordinances, and resources for further information.


Wetlands are fragile ecosystems that serve important beneficial functions, such as assisting in the reduction of erosion, siltation, flooding, ground and surface water pollution, and providing wildlife, plant, and fisheries habitats. Wetlands include swamps, marshes, bogs, and similar areas. Wetlands are identified as critical areas in the Washington State Growth Management Act (RCW 36.70A.030(5) and RCW 36.70A.060). This page provides information of use to local governments in their wetlands regulation and permitting functions.

In Washington State, the Department of Ecology is charged with protecting, restoring, and regulating wetland resources. Two state laws, the State Water Pollution Control Act and the Shoreline Management Act, give Ecology the authority to regulate wetlands. Ecology also uses the State Environmental Policy Act (SEPA) process to identify potential wetland-related concerns early in the permitting process.

Wetlands are rated according to a system that organizes wetlands into four categories based on wetland functions, sensitivity to disturbance, rarity, and ability to replace them. Wetland delineation involves determining the edge of a wetland based on three parameters: water, plants, and soil.

Strategies for saving wetlands and other critical areas include limiting uses and avoiding development in some areas, transferring development density to another site or a non-sensitive portion of a large site, and public purchase of valuable or unique wetlands. Buffer areas around wetlands and along streams are also used to protect the functions of these critical areas. Mitigation of impacts on wetlands and other critical areas involves reducing the adverse impacts of a project to an acceptable level. In addition to critical areas regulations, nonregulatory and incentive programs are also used to protect wetlands.

Many local governments hire wetland experts to prepare and update wetlands ordinances. Local governments also require developers to do special studies of wetlands located on a proposed development site. Some jurisdictions have prepared lists of preferred wetlands consultants.

Statutes and Administrative Regulations


Administrative Regulations

Federal Resources

This section includes information on wetlands regulations and protection from federal agencies that is relevant to local governments.

U.S. Environmental Protection Agency (EPA)

U.S. Fish & Wildlife Service

Washington State Resources

Washington State departments, especially the Department of Ecology, offer excellent information on wetlands protection and resources. Under the Growth Management Act, local governments are required to use the best available science when reviewing and revising their policies and regulations on wetlands.

Washington Department of Ecology

Governor's Office for Regulatory Innovation and Assistance (ORIA)

  • Wetland Permits – Environmental Permit Handbook (Scroll to bottom to view)

Local Ordinances and Informational Handouts

This section includes selected local ordinances from Washington jurisdictions and development assistance handouts on wetlands.

Codes and Ordinances

Development Assistance Handouts on Wetlands

Recommended Resources

The following are general websites and webpages that provide guidance on wetlands protection.

Last Modified: January 24, 2023