Washington State Department of Ecology, Environmental Assessment ProgramThe Washington State Department of Ecology has conducted monthly water quality monitoring at hundreds of freshwater and marine water quality stations throughout the state since 1959. Ecology monitors about 80 stations each year, some on a one-year basis, some on a five-year rotation, and some are monitored continuously. This spatial data set shows the location of these monitoring stations.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/d57c943be6354d4788c8a8f92030acbc_0engState of Washington Geospatial Open Data PortalPublicDepartment of Ecology Ambient Monitoring Stations [Washington (State)]Web servicesWashington (State)Last Modified: 2025-12-29