Department of Ecology
Committees, Boards, and Workgroups

Ecology's Water Resources Program is the state's managing entity for its water resources. We issue water rights, ensure compliance with authorized water use, and plan and fund projects that improve water availability and streamflows.

Like many other states in the western United States, Washington manages its water resources based on principles of the prior appropriation doctrine. Water is a public resource held for all to use, and private individuals establish the right to water use through an appropriation to apply that water to a beneficial use. These water rights are usufructuary, meaning that water right holders must continue to use their appropriation to maintain the rights to its use; if use diminishes or ceases for a certain amount of time, that unused appropriation is relinquished to the state. Priority between existing uses is based on seniority, so when conflicts over limited water uses arise, senior uses are satisfied in full before junior uses receive any amount.

Parties seeking to use water are free to appropriate water for a new use, provided that:

• water is physically and legally available for appropriation;
• other existing water uses will not be impaired by the new use;
• the new use qualifies as a beneficial use; and
• the new use will not impair the public interest.

In practice, however, there is very little water still available for appropriation in many of Washington's watersheds. In these areas, parties seeking new supplies must generally seek to adapt existing appropriations to meet their needs, either through the direct transfer of an existing right to a new location and/or use or else by providing mitigation through Ecology's Trust Water Rights Program. Considerations of the public interest for these transfers depends on the transfer mechanism and the watershed context.

Background Reading

• Final Legislative Report on Water Right Transfers, Water Banking, and Trust
  • Public Interest Draft Discussion Paper
• Final findings and recommendations: Advisory Group on Water Trust, Banking, and Transfers
• Washington Water Law Primer
• The Water Report - Washington State Rural Water Strategies
• The Water Report - Instream Flow Management in Washington
• The Water Report - An Examination of Public Interest in Washington Water Law
• Landowner's Guide to Washington Water Rights
• Washington Water Rights Explorer
• Restoring the Public Interest in Western Water Law

Contacts

• Washington state contacts (coming soon)
• Other western state agencies

Info Session Slides

• Water Rights 101
• Public Interest Discussion

Case Law and Decisions

• Swinomish v. Ecology (2013) - Ecology cannot use overriding consideration of public interest to authorize water uses that will impair mandated instream flows
• Ecology's decision on US Golden Eagle/Darrington - Ecology recently ruled against use of a trust water right for mitigation based on its public interest evaluation

Previous Evans School Projects

• Water Banking and Water Marketing in Select Western States (2019)
• Evaluating the Impact of Out-of-Basin Water Rights Transfers in Washington State (2021)

Reference Materials

• Oxford Handbook of Water Politics and Policy
• Water Resource Economics
• An Introduction to Washington Water Law

Statutes

Title 90 Water Rights - Environment

• RCW 90.03 - Water Code
  • 90.03.290 - New appropriations must be nondetrimental to the public welfare
• RCW 90.42 - Trust Water Rights
  • 90.42.040(2)(a) - Exercise of a trust water right may not impair the public interest
• RCW 90.44 - Groundwater rights
  
  • 90.44.100(2) - Groundwater right change applications also subject to 90.03.290 requirement ("findings as prescribed in the case of an original application)
• RCW 90.54 - Water Resources Act of 1971
  • 90.54.020 - General declaration of fundamentals of water use; includes considerations of public interest
• RCW 90.82 - Watershed Planning
  
  • 90.82.130(4) - Watershed plans created under 90.82 process are a "primary consideration in determining the public interest"

Oregon and Idaho public interest statutes related to water resources