This data release contains vector shapefiles of gridded, monthly water use estimates for the United States part of the Salish Sea basin in northwestern Washington for the year 2017. The water use estimates are provided by category of use for public supply, domestic self-supply, agriculture, and aquaculture each and are further distinguished by surface water or groundwater sources. Data to compute these water use estimates were provided by various Washington state agencies including Washington State Department of Health, Washington State Department of Ecology, Washington State Department of Agriculture, and Washington Geoservices. Additional data used include county-level water use estimates for 2015 from the U.S. Geological Survey and monthly fractions of water use estimates (Welch and others, 2024). Copies of the shapefile attribute tables are also included as comma separated value (CSV) files as part of this data release.