Water Quality photo identifier

Water Quality Program

Water Quality Assessment (303[d]) & Water Quality Improvement

Water Quality Assessment (303[d])

The Water Quality Assessment lists the water quality status for a particular location in one of 5 categories recommended by EPA. The assessment represents the Integrated Report for Sections 303(d) and 305(b) of the Clean Water Act.

General 303(d) List Information | Current Assessment | Upcoming Water Quality Assessment | more

Water Quality Improvement

This website provides information to help residents, stakeholders, and policy makers understand the complex issues around improving water quality, find out what Ecology is doing to clean up our waters, and help each person learn what they can do to help keep our rivers, lakes, and marine waters clean.

Water Quality Improvement Home Page | Total Maximum Daily Loads (TMDLs) in Your Watershed

Data Quality Assurance

Information on water quality data assurance - what it is, why it is important, and what the State of Washington is doing to support quality assurance of water quality data.

General Data Quality Information | Data Quality Policies