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Using river & stream water quality data

Find and use the Statewide Water Quality Network to learn about the status and health of rivers and streams across Washington. Learn how to find the application and how to use it to navigate through information on rivers and streams.

Finding river and stream water quality data

Accessing data by map

The map-based application, the Statewide Water Quality Monitoring Network, provides data about water quality for many rivers and streams in Washington. The blue squares indicate long-term stations that are sampled once a month, often for many years. The yellow squares indicate basin stations, sampled once a month during every fifth sampling season. Click on the station for which you want data, and a pop-up box will appear. Select the blue link inside that box to go to the station page. See below for navigating station pages.

See Water quality monitoring methods for rivers & streams to learn more about what is measured.

Navigating station pages

Each water quality monitoring station found on the map has its own station page. On these pages, there is usually a photo of the station and a table of station details, including a scientist to contact with any questions.

A year grid shows yellow-shaded squares on years for which there is sampling data. A small WRIA (watershed) map shows the location of the station and links to other stations within the WRIA. A pull-down menu listing WRIAs is a quick method to jump to data for other watersheds.

A 22 by 3 contains numbers. These number signify years, so the first is 17 for 2017, and the last is 52 for 1952. Text above:

The water quality data tabs

At the bottom of the page, there are from four to six tabs of information. Information about what is under each tab is shown below.

Six tabs include Station overview, Water Quality Index, Criteria, Finalized data, Preliminary data, and Temperature. Station overview is selected.

Station overview

The station overview tab includes more details about the location and a box that notes whether water quality is a concern at this location.

Water Quality Index

The Water Quality Index tab contains information about the Water Quality Index (WQI). The WQI is a graphic overview or summary of the water-quality conditions at the station. It uses a numeric score of up to 100 and blue, beige, and red bars on graphs to demonstrate the water quality for different measured parameters at the station, and showing overall monthly and yearly trends.


The criteria tab includes tables of data for which parameters did not meet the surface-water-quality standards as defined by Washington state law in Chapter 173.201A WAC.

Finalized data

Finalized data usually takes two years to be posted, including one year for analysis and one year for quality control. There is a summary table and a link to download complete data sets.

Preliminary data

Preliminary data are available for recently sampled stations, and this tab contains the latest values. These are subject to change based on quality-control checks.


Water and air temperature are collected on a real-time basis for some stations during the summer. More information is available at Temperature monitoring.