Water Quality Assessment & 303(d) List

Before starting the 2018 Assessment, we completed a comprehensive update of our Water Quality Assessment policy (Policy 1-11) from 2016 to 2018. We then conducted a call for data in 2018, and received 116 million pieces of data collected between 2006 and 2017. Due to the large volume of data that were available for Washington, we developed new data tools to automate much of our Assessment process. The development and testing of these new automation tools was completed in Spring 2020. Data analysis began soon after tool development. We held a public comment period on our draft Assessment from April 2021 – June 2021. The candidate Water Quality Assessment was submitted to EPA on Aug. 31, 2021. EPA issued a partial approval of our candidate Assessment on June 8, 2022 and their final approval on Aug. 26, 2022.

To develop the next Assessment, we first need to review and update our Water Quality Assessment policy (Policy 1-11). The purpose of the update is to provide additional and clarifying information in select sections of the policy, based on comments and questions we have received. 

In March 2023, we updated Policy 1-11. This update included a new methodology for evaluating freshwater harmful algae blooms, a temporary suspension of the natural conditions methodology, and non-substantial edits to improve clarity of the Water Quality Assessment, largely focused on listing based on narrative standards. Policy 1-11 was also shifted to an updated, accessible format. The public comment period was open Nov. 7, 2022 – Jan. 6, 2023.

2022 Water Quality Assessment call for data, to help us understand the condition of state water bodies, was open July 7, 2022 – Sept. 30, 2022. For this Assessment, we analyzed data and information collected between Jan. 1, 2012 and Dec. 31, 2021.

Water quality data was submitted to Ecology's Environmental Information Management (EIM) database. Narrative information and studies, such as published research and peer-reviewed reports, were submitted directly to Water Quality Assessment staff at 303d@ecy.wa.gov.

The next step is to compile and assess water quality data from Washington’s rivers, streams, lakes, and marine waters. Under Policy 1-11, we will evaluate the data and determine where designated uses of Washington's waters are impaired.

We used the updated Policy 1-11 to evaluate the data quality and review Washington's water bodies to determine where designated uses are impaired. The result is the draft revised Water Quality Assessment. We completed data analysis in Summer 2024.

We are currently in this step.

The public comment period usually lasts 60 days. It is an opportunity for people to comment on draft Assessment results. Before and throughout the public comment period we also seek feedback from Tribes.

During the public comment period, we host a workshop to discuss the Assessment process, key changes in the Assessment, data results, and provide a demonstration of how to use review tools and submit comments.

After the public comment period, we will make changes to the Water Quality Assessment, provide a detailed response to comments, and submit the candidate Water Quality Assessment to EPA. EPA has 30 days from the time we submit the Assessment to take action. Once approved, the candidate Water Quality Assessment will become the new, approved Water Quality Assessment for Clean Water Act regulatory purposes. We will then begin the whole process again – starting with reviewing Policy 1-11 and announce a call for data for the next Assessment cycle.

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.