Water Right Adjudications

Last updated: August 2, 2017

Adjudication is a legal process to determine who has a valid water right, how much water can be used, and who has priority during shortages. It is currently the only definitive and legally binding way to make these determinations. For sound water management, it is just as important to know about the legal availability of water (law/water rights) as it is to know about its physical availability (hydrogeology).  

Adjudication provides a thorough accounting of water which is essential to water resources use, protection and planning, as well as the transfer of water rights. It is key to resolving and preventing water conflicts in an era of increasing water demands and water supply impacts of climate change.

Persons claiming a right to use water make their claim in a local Superior Court. Adjudications can range in size and scope from small (such as the rights of two water right holders with respect to one another) to large (such as the Yakima River Basin) that settle all the rights in a particular water system (a “general adjudication”). They can include surface water, groundwater, or both.

Since 1918, 82 basins have been adjudicated under state water rights adjudication law. (See also a list of active, completed, and incomplete adjudications; and areas petitioned for adjudication.)  There have also been some adjudications under federal law.

There is currently only one active adjudication in Washington, the Yakima River Basin Surface Water Adjudication.

Yakima River Basin Surface Water Adjudication (Acquavella)

The Yakima River Basin adjudication includes Benton, Kittitas and Yakima counties, and a small portion of Klickitat county.  Started in the late 1970s, it will result in the confirmation of some 3,000 water rights affecting several thousand water users in the Yakima Basin.

Draft Acquavella Certificate of Adjudicated Water Right

Draft schedule of rights and court documents list

Recent Yakima County Superior Court Activities

Forms and Instructions for those currently involved in the Yakima Adjudication

The following are suggested forms approved by the Court to divide a water right or to join or substitute owner(s) of property for which a Court claim has been filed.

Pre-trial Order No. 3 -- Property Ownership Change - The County does not report property sales. It is your responsibility to file the appropriate documents with the Court when you sell or transfer your property or portion of your property.

Map of Major Claimants and Subbasins

Background and Historic Information

Other Adjudication Information

Spokane Area Water Right Adjudication

Preliminary work in preparation for a Spokane area adjudication has been completed.  Further action leading to a formal start of the adjudication s is currently on hold, pending funding and a formal decision to proceed.  As Idaho completes their Northern Idaho Adjudication, the Spokane area adjudication is essential to ensuring that Washington rights to shared waters are protected.

Adjudication of Lake Levels

The adjudication of lake levels is a separate process from water right adjudications, although there may be some overlap. Washington state law (RCW 90.24 Regulation of outflow of lakes) allows lake residents to petition superior court for an order to regulate lake levels. This may be requested for a variety of reasons, including aesthetics, recreational needs and flood control.

Regulation of lake levels is usually handled on a case-by-case basis, depending on the reason for the request.  In addition to an adjudication under RCW 90.24, other situations in which lake levels may be set include:

More Information on Washington Water Law and Water Rights

(Please note that these publications and web pages do not provide legal advice – if you have questions requiring a legal opinion, you may need to consult an attorney.)

Contact Information

Dave Christensen
Leigh Bedell - Staff
(360) 407-6017
  Mike Thomas - Staff
(360) 407-6599