River & stream water quality index

See how your river or stream is doing

Data  presented in the Water Quality Index, or WQI, helps indicate whether water quality is good, meeting standards to protect aquatic life, whether it is of moderate concern or is poor and doesn't meet expectations. The Index ranges from 1 to 100; a higher number indicates better water quality.

The WQI graphs show blue for low concern, beige for moderate concern, and red for high concern or poor water quality. 

Find the Water Quality Index

The Water Quality Index is in a tab on individual station pages in the Statewide Water Quality Monitoring Network application. Select your station of interest from the application map, and click the blue link to get to the station page. The tabs are toward the bottom of the page. Click on the Water Quality Index tab to find the WQI graphs.

Most pages show trends over time, though the amount of time covered varies by station. Each page has four graphs: scores for the most recent water year (October through September), scores by constituent, scores by month, and general WQI score trends for that station year-by-year. The "scores by constituent" include eight analytes/parameters, including fecal coliform bacteria, dissolved oxygen, and temperature.

Calculate WQI based on your own data

The Water Quality Index spreadsheet (Version 6) is a downloadable tool for calculating a WQI score based on your own data.

Learn about the methodology

A Water Quality Index for Ecology's Stream Monitoring Program is a report that describes the development of and the methodology for the Water Quality Index.