Polygons depict 10 year time of travel estimates for active group a public drinking water supplies. Source location data were obtained from the Washington State Department of Health, Office of Drinking Water. This layer is used in the Source Water Assessment Protection application https://fortress.wa.gov/doh/swap/index.html.  Data is updated Monday mornings.  Check the "Data updated:" date in the Details section.  Metadata dates are not automatically updated.