Municipal Water Law


In 2003, the The Washington State Legislature significantly amended Washington water law to provide clarity on the nature of water rights issued for municipal supply purposes, and to provide flexibility to municipal water suppliers in exercising their water rights.  The Municipal Water Law defines the terms “municipal water supplier” and “municipal water supply purposes”, defines when the “place of use” could be the same as a municipal water suppliers service area, establishes that municipal water rights were not limited to the stated number of connections but to the number of connections approved in a water system plan, and required specific conservation practices and planning.  Under the law, utilities must use water efficiently.

The Washington Departments of Health and Ecology share responsibilities under the Municipal Water Law, and have developed agreements to coordinate planning, engineering, and public health and safety matters relating to water systems and water resources.  The Department of Health is responsible for ensuring safe and reliable drinking water, and reviews and approves planning and engineering documents for water systems.  The Department of Ecology administers Washington State’s Water Resource Program, including water rights administration and watershed planning.

The regulation of municipal water is an important element of water management in Washington State.  This web page is reserved for issues relevant to the 2003 Municipal Water Law - Municipal Water Supply – Efficiency Requirements Act Chapter 5, Laws of 2003.

Municipal Water Law Interpretive and Policy Statement

The Department of Ecology developed an Interpretive and Policy Statement (IPS) for carrying out the 2003 Municipal Water Law under the authority of the Administrative Procedure Act - RCW 34.05.230.  This policy statement clarifies the Department of Ecology’s position and management approach for carrying out that law for the primary audience of those interested in, and affected by, management of water rights for municipal supply purposes.  This policy statement also enables Department of Ecology staff to have a common understanding and consistency of application.

POL 2030 - 2003 Municipal Water Law Interpretive and Policy Statement - Revised (05/07/2012)

Washington Supreme Court - Scott Cornelius, et al v. WA Department of Ecology, et al.

Memorandum of Understanding

The Department of Health, Office of Drinking Water and Ecology's Water Resources Program have developed Memorandum of Understanding (MOU) and Joint Review Procedures to outline the agencies’ roles and responsibilities so they might better coordinate their actions on aspects of their missions that overlap.  The most recent update to the MOU includes new coordination procedures that had to be developed as a result of the passage of the 2003 Municipal Water Law:

Presentations, Information and Links


General Information

Information Sources (Links)

For More Information

Archive page of past documents and information - Includes all information posted on the web up to and including the October 28, 2010 Supreme Court Decision in Lummi Indian Nation v. State, the constitutional challenge to the Municipal Water Law


For region-specific information about Municipal Water
Northwest Region - Bellevue
Counties:  Island, King, Kitsap, San Juan, Skagit, Snohomish and Whatcom

Doug Wood
Office: 425-649-7077

  Southwest Region - Lacey
Counties:  Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Mason, Lewis, Pacific, Pierce, Skamania, Thurston and Wahkiakum

Mike Gallagher
Office: 360-407-6058

Central Region - Union Gap
Counties:  Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan and Yakima

Scott Turner
Office: 509-457-7106

  Eastern Region - Spokane
Counties:  Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla and Whitman

Dan Tolleson
Office: 509-329-3526