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freshwater monitoring

Freshwater Monitoring

Using River and Stream Water Quality Monitoring Data

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 State. The blue squares indicate long-term stations, sampled once a month, often for many years. The yellow squares indicate basin stations, sampled once a month, often every five years. 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.

Accessing data by Water Resource Inventory Area

If you know the Water Resources Inventory Area or WRIA for your river or stream of interest, you can find data for monitoring stations in that area using the drop-down menu below. A WRIA is the area included in one watershed and that is inside of Washington State boundaries.

Select a Washington Watershed by Zip Code can help you find your WRIA name and number, as can this WRIA map. Once you know your WRIA, use the drop-down menu below to go to your watershed's first station page in the Statewide Water Quality Monitoring Network application. From there, the listing under the map on the right-hand side of the page contains the stations in that WRIA.

Select from a WRIA list

Navigating station pages

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

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

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 below.

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 WAC 173.201A.

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.