2012 Water Quality Assessment

The 2012 list is available for informational and reference use only.

Use the most recent 303(d) list to be approved by EPA for the purposes of writing discharge permits, watershed characterization, financial assistance funding, TMDL prioritization, and TMDL implementation.



The water quality assessment fulfills the state's obligation to submit a 2010 integrated report to meet the Clean Water Act requirements of sections 305(b) and 303(d).

The Environmental Protection Agency (EPA) approved the 303(d) list on December 21, 2012.

Key Issues Related to The 2012 EPA-Approved Assessment

The 2012 EPA-approved water quality assessment includes assessment of new data for marine waters, and specific changes that resulted from the public comment period. It also includes changes in Category 5 listings to Category 4A where a total maximum daily load (TMDL) was approved since the last listing cycle.

A key issue related to this marine assessment was whether Ecology should list all Washington State waters on the 303(d) list for pH due to impairments from ocean acidification. Ecology conducted a review of all data and studies, but was not able to substantiate impairment to Washington’s coastal waters for ocean acidification based on credible data. However, Ecology’s review of recent studies did result in a decision that there was enough credible information to list Puget Sound waters in Category 2 (waters of concern) for potential impacts to fish and shellfish habitat from human activities. This includes conditions that make the waters more vulnerable, such as climate change, urbanization, and ocean acidification. Concurrently, Washington’s Governor established a Blue Ribbon Panel of science and policy experts to address ocean acidification issues, especially as they relate to the health and protection of shellfish. The work of the Blue Ribbon Panel resulted in the Governor’s Executive Order 12-07, which included several recommendations to address the effects of ocean acidification on Washington’s shellfish resources and other marine organisms. Information on the Governor’s direction on ocean acidification efforts can be found on Ecology’s website at www.ecy.wa.gov/water/marine/oceanacidification.html.

As part of the Governor’s Blue Ribbon Panel recommendations, Ecology’s Director sent a formal request to the Environmental Protection Agency, on December 24, 2012, asking that they begin an assessment of water quality criteria relevant to ocean acidification. EPA Acting Assistant Administrator Nancy Stoner responded on April 19, 2013, noting that EPA plans to establish a technical workgroup to evaluate data and research regarding water quality parameters most relevant for understanding and addressing ocean acidification and its causes.

Water Quality Process

The current water quality assessment and 303(d) list is based on the state water quality standards (Chapter 173-201A WAC, 2006 version) and sediment management standards (Chapter 173-204 WAC) approved by EPA. The methods for assessing the data and information are based on these standards and described in the 2006 version of Ecology’s Water Quality Program Policy 1-11, which is available by request.

Public Review

Call for Data

Data Compilation and Assessment

Most of the data used in the Assessment are housed in Ecology's EIM database. We also received data from other sources, such as EPA's STORET database and the USGS NWIS database.

Submittal to EPA

EPA Approval

If you have questions or need specific information on the 2012 assessment, please contact:

Patrick Lizon
Water Quality Program
WA Department of Ecology
P.O. Box 47600
Olympia, WA 98504-7600
Email: 303d@ecy.wa.gov


Last updated July 2016