The water quality assessment is our process of collecting data and assessing the quality of surface water in the state. This includes all rivers, lakes, and marine water. You can view the results of the assessment in our online database.
The federal Clean Water Act requires that all states restore their water bodies to be “fishable and swimmable.” Section 303(d) of the Clean Water Act establishes a process to identify and clean up polluted water.
What is the Water Quality Atlas?
We also have a mapping tool called the Water Quality Atlas. The Water Quality Atlas is an interactive search and mapping tool that includes additional layers of information in an easy-to-use mapping application.
Users can map the water quality assessment category results, view water quality standards for a location, identify areas addressed by Total Maximum Daily Loads (TMDLs), and see permitted wastewater discharge outfalls.
The current assessment
The current water quality assessment — called the 305(b) report and 303(d) list of impaired waters for the state of Washington — was approved by the U.S. Environmental Protection Agency (EPA) on July 22, 2016. See below for more information about the current process to update the assessment.
Read the 2016 EPA approval letter.
Key changes that were made in 2016
- Updated freshwater listings based on data collected between 2000 and 2010.
- Updated how we map polluted rivers, lakes, and streams — moving from a land-based system (township/range/section) to a water-based (National Hydrography Database) system. The mapping change helps us be consistent with other agencies and states, and is strongly recommended by EPA.
The process to update the Water Quality Assessment
The following timeline provides information on each step of the current assessment cycle. Because we have been working on a large data automation project (see Assess the data section below) we have not submitted an assessment since 2016. However, this automation of our data should now allow us to meet our requirement for submittal every two years. This new assessment will serve as Washington's past due submittals.
The opportunity for early tribal review of the assessment is part of a 1997 cooperative agreement between the tribes, Ecology, and EPA that recognizes the government-to-government relationship between Washington and tribes in managing water quality.
To develop the revised assessment, we first needed to review and update our water quality assessment policy (Policy 1-11). The purpose of the update was to include several revisions to Washington's surface water quality standards and respond to comments received in the public review of the policy.
Next, we gathered readily available data and narrative information to help us understand the condition of state water bodies. To do this we used federal databases and asked other groups to submit their data to our Environmental Information Management System (EIM). Our call for data and narrative information happened in 2018 and we recieved approximately 116 million pieces of data. The updated assessment will reflect all data and information collected through 2017. Water quality condition determinations based on data prior to 2006 are only reassessed if newer data and information are available.
We applied the updated Policy 1-11 to evaluate the data quality and used the data to review all of Washington's water bodies to determine where designated uses are impaired. The result is the draft revised water quality assessment.
Due to the large volume of data that are available for Washington, we developed new data tools to automate much of our process. These tools will help us gather data more frequently and provide the Assessment to EPA every two years. The development and testing of these new automation tools was completed in Spring 2020 and are now being used to create the draft Water Quality Assessment.
We will hold a public comment period, including a public webinar, to gather public input on the draft assessment. We will use comments to improve and finalize the final assessment list.
We then submit the new water body listings, which include the 303(d) list of impaired waters, to EPA for approval. We hope to have this complete by the end of 2021.
How are water bodies assessed?
We compile our own water quality data, and invite other groups to submit water quality data they have collected. We only assess data that meets high quality assurance and credible data requirements . Our goal is to accurately determine if water bodies are polluted based on the best available data.
The assessed water bodies are placed into one of five categories that describe the water quality. Once the assessment is complete, we provide the public a chance to review and give comments. We submit the final assessment to the Environmental Protection Agency for approval of the category 5 listings, also called the 303(d) list.
Assessment categories
Category 1 means a water body meets the state water quality standards. Being placed in this category does not necessarily mean that a water body is free of all pollutants.
Most water quality monitoring is designed to detect a specific array of pollutants, so placement in this category means that the water body met standards for all the pollutants for which it was tested. Specific information about the monitoring results may be found in the individual listings.
Water bodies in this category have some evidence of a water quality problem, but not enough to show persistent impairment. These are water bodies that we want to continue to test.
There are several reasons why a water body would be placed in this category. A water body might have pollution levels that are not quite high enough to violate the water quality standards. Or there may not have been enough violations to categorize it as impaired according to our listing policy.
According to Policy 1-11, Category 3 water bodies have insufficient data to place them into any of the other categories.
Category 4 means water bodies that have impairment problems are being resolved in one of three ways:
- Category 4a — already has an EPA-approved TMDL plan in place and implemented.
- Category 4b — has a pollution control program, similar to a TMDL plan, that is expected to solve the pollution problems.
- Category 4c — is impaired by causes that cannot be addressed through a TMDL plan. Impairments in these water bodies include low water flow, stream channelization, and dams. These problems, while not pollutants, require complex solutions to help restore water bodies to more natural conditions.
Water quality assessment Category 4b
We recognize that communities do not have to wait for a formal TMDL planning process to begin improving water quality. They can take the initiative to clean up polluted water. Because these efforts are locally controlled, there is an opportunity to reduce overall costs, and the communities can exert greater control over the cleanup process.
Category 4b is intended for water bodies with a pollution control program in place that is expected to solve the pollution problems. While pollution control programs are not TMDLs they must have many of the same features. There must also be some legal or financial guarantee that the program will be implemented.
To be placed in the "has a pollution control project" category, the pollution control project must meet all of the following criteria:
- Be problem-specific and water body-specific
- Have reasonable time limits established for correcting the specific problem, including load reduction or interim targets, when appropriate
- Have a monitoring component to evaluate effectiveness
- Have adaptive management built into the plan to allow for course corrections, if necessary
- Have enforceable pollution controls or actions stringent enough to attain the water quality standard or standards
- Be feasible, with enforceable legal or financial guarantees that implementation will occur
- Be actively and successfully implemented and show progress on water quality improvements in accordance with the plan
In addition to the conditions above, the project is more likely to gain approval if the following elements are included:
- A description of management measures
- An implementation schedule and measurable milestones
- A description of criteria that are used to determine loading reductions achieved over time
- An information/education component
This is the list of impaired water bodies traditionally known as the 303(d) list. Starting with the 2004 Water Quality Assessment, Washington’s 303(d) list of polluted waters were placed under category 5 in the approved assessment. Total Maximum Daily Loads (TMDLs) or other approved water quality improvement projects are required for the water bodies in this category.
If a water body is in this category it means that we have data showing that the water quality standards have been violated for one or more pollutants, and there is no TMDL — or pollution control program — in place.
303(d) list
Water bodies whose designated uses (such as for drinking, recreation, aquatic habitat, and industrial use) that are impaired by pollutants are identified in the water quality assessment as "Category 5: Polluted water that requires a water improvement project." The 303(d) list, so called because the process is described in Section 303(d) of the Clean Water Act, lists water bodies in the polluted water category.
Federal laws, state water quality standards, and water quality assessment policy 1-11 guide our assessment of which water bodies to place on the 303(d) list.
To view the list, go to the water quality assessment database and select Category 5 (under Categories).
What happens to polluted water bodies?
If water bodies are polluted, we develop a water cleanup plan, also called a Total Maximum Daily Load or TMDL, to reduce pollution sources throughout the surrounding watershed. After pollutant controls are in place, we monitor in the watershed to see if the water meets state water quality standards.