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Streamflow restoration

Washington state has a new streamflow restoration law in response to the “Hirst decision.” Hirst was a 2016 Washington State Supreme Court decision that changed how counties approve or deny building permits that use permit-exempt wells for a water source. Engrossed Substitute Senate Bill 6091, was passed on Jan. 18, 2018, and signed by Gov. Inslee the next day.

The law, RCW 90.94 Streamflow Restoration, helps protect water resources while providing water for families in rural Washington. We are getting started on implementation and look forward to working with communities to help find water supply solutions for homes and to protect streamflows for fish.

What does the law do?

  • The law focuses on 15 watersheds that were impacted by the Hirst decision and also establishes standards for rural residential permit-exempt wells in the rest of the state. The law divides the 15 basins into those that have a previously adopted watershed plan and those that did not. 
  • The law allows counties to rely on our instream flow rules in preparing comprehensive plans and development regulations and for water availability determinations.
  • It allows rural residents to have access to water from permit-exempt wells to build a home.
  • It lays out these interim standards that will apply until local committees develop plans to be adopted into rule:
    • Allows a maximum annual average for new domestic water use, depending on the watershed.
    • Establishes a one-time $500 fee for landowners building a home using a permit-exempt well in the affected areas.
  • It retains the current maximum of 5,000 gallons per day limit for permit-exempt domestic water use in watersheds that do not have existing instream flow rules. 
  • It invests $300 million over the next 15 years in projects that will help fish and streamflows.

Policy interpretation

We are working to interpret key provisions of the law. 

Interim guidance documents

Public input requested

We are requesting public input on two actions related to the Streamflow Restoration law: 
  • A new rulemaking for Chapter 173-566 WAC - Streamflow Restoration Funding Program. The rulemaking will establish process and criteria for funding projects statewide under RCW 90.94.060
  • Preparing final guidance for determining Net Ecological Benefit (NEB). The Streamflow Restoration law requires us to determine that NEB will result from implementing plans and projects as described in the law. In June 2018, we issued interim guidance on NEB for planning groups on expedited planning tracks, and for pilot projects being conducted under Section 301 of the law. The final NEB guidance will be used to evaluate watershed plans that are completed as directed under RCW 90.94.020 and RCW 90.94.030. We anticipate publishing the final NEB guidance in early 2019.


We expect the Streamflow Restoration Funding Program and the NEB guidance will be of interest to entities involved in protecting, restoring, and enhancing streamflows and instream resources. We would like to hear your input and feedback as we develop these two tools. We will host six two-hour public workshops in October, with the first hour dedicated to discussing the funding rule, followed by a discussion of the NEB guidance.

Questions and answers

Are counties that restricted building permits in response to the Hirst decision now issuing building permits? Which wells are impacted by this law? When will information about plan evaluation and funding be available? What’s the difference between basins with and without a watershed plan? When did the law take effect? How will the $300 million be used? What is the Hirst decision? What counts as a permit-exempt use of groundwater?