Revising the Water Quality Assessment & Policy 1-11

The Clean Water Act requires states to regularly assess readily available water quality data and report on the status of the state's surface waters. The U.S. Environmental Protection Agency (EPA) approved Washington's most recent water quality assessment in 2016.

The process to update the Water Quality Assessment

We are currently working to update the water quality assessment (WQA). To develop the revised WQA we first review and update our water quality assessment policy (Policy 1-11). The purpose of the update is to include any recent changes to Washington's surface water quality standards and respond to comments recieved in the public review of the policy. The next step is to gather readily available water quality data and apply the final policy to make listing decisions and place waterbodies into categories. We then submit the new waterbody listings, which include the 303(d) list of impaired waters, to EPA for approval.

Where we are in the Water Quality Assessment Cycle

Updates to the policy are completed

The updates to our water quality assessment guidance were completed in two phases. In Nov. 2018, we made major revisions to water quality Policy 1-11, Chapter 1: Assessment of Water Quality for the Clean Water Act Sections 303(d) and 305(b) Integrated Report. This policy guides the process for reviewing data and using that data to list waters within certain categories in the WQA. 

In 2019, in a separate process, we adopted and the EPA approved, new bacteria criteria that protect Washington waters for recreation activities. This change in criteria meant we had to further update Policy 1-11. In April 2020 we updated the policy, held a public review, and responded to comments received. We  finalized the policy in July 2020. 

Assessing the data

We gathered available data from the public in 2018 and are now in the process of applying the new policy to evaluate the data and develop the revised water quality assessment. Due to the the large volume of sampling data that are available for Washington waters, Ecology has developed new data assessment tools to automate much of our process. These tools will help us gather data more frequently and provide the WQA to EPA every two years. The development and testing of these new computing tools was completed in Spring 2020 and are now being used to create the draft Water Quality Assessment. We plan to complete the draft in 2020, then we will hold a public comment period to gather public input. We will use comments to improve and finalize the final assessment list and then submit to EPA for approval.

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