Water right adjudications

A water right adjudication is the legal process to resolve conflict and competition on a water source. Adjudication legally determines whether each water right on a source is legal, how much water can be used, and its priority during shortages. A watershed-wide adjudication prioritizes each individual water right, including federal, tribal, and instream flow rights, under Washington water law's “first-in-time, first-in-right” prior appropriation framework. When there is not enough water for everyone, the water users who have been there longest have priority.

Ecology’s Water Resources Program is responsible for managing the state’s water resources. Adjudication is an important process to make sure water regulation is fair and everyone follows the same rules.

Recent actions

In May 2019, the Yakima County Superior Court completed its adjudication process for the Yakima River Basin. This process determined surface water rights for about 2,300 water rights. Ecology is providing water users with adjudicated certificates, which show their water right’s extent (quantity) and priority. The Yakima adjudication is the only general stream adjudication completed for an entire watershed in Washington. However, there have been more than 80 small stream adjudications and multiple federal adjudications. When an adjudication is complete, we will ensure that everyone complies with their legal water right.

Whatcom Falls. Photo by Scott Beckner

The future of adjudications

During the 2019 legislative session, the Legislature provided us funding to assess the needs and benefits of future adjudications. We looked statewide to assess watersheds that might benefit from adjudication, considering basins with senior tribal water rights, streamflow needs, and challenges caused by water user uncertainty and conflict. We conducted extensive outreach, met with tribes and local governments, and compiled water right, history, and habitat information.

Recommendations resulting from our 2020 assessment include:

  • Begin adjudication proceedings in the highest priority watershed — Nooksack Watershed (WRIA 1), and Lake Roosevelt and middle tributaries (WRIA 58).
  • Consider future adjudications in other prospective watersheds — Spokane River basins (WRIAs 54, 55, 56, and 57), and Walla Walla River (WRIA 32).
  • Gather more information on additional watersheds to see whether these would benefit from future adjudications — Skagit River system (WRIAs 3 and 4), Chehalis (WRIAs 22 and 23), Methow (WRIA 48), and groundwater rights in the Yakima River basin (WRIAs 37, 38, and 39).

Read our Frequently Asked Questions for Nooksack Basin (Lake Roosevelt is coming soon!).

Advances in law and technology will make future adjudications more efficient and less complicated than past proceedings. Our next generation of adjudications will focus on high-priority watersheds with a new streamlined process.