King CountyFor more information about this layer please see the GIS Data Catalog . Sump Components--Grate Inlet Type 1: A structure that is rectangular and has a rectangular, metal grate and a Sump; cannot support traffic loads. Interior Dimensions 23" Wide x 42" Long x Variable Depth, 12' Max.; Max Depth to Pipe invert is 9' 6". For more detail see WSDOT Standard Plans (B-35.20-00).--Catch Basin: A structure that functions with a Sump to either allow for water to enter a conveyance or control features or a connection of the stormwater management system to surface or subsurface flows. Catch basins are circular or rectangular and usually have a grated metal lid or cover.No Sump Components--Concrete/Curb Inlet: A square shaped structure similar to a Type 1 Catchbasin without a Sump. These structures are generally used to accept stormwater inflow through a curb opening.--Grate Inlet Type 2: A structure that is rectangular and has a rectangular, metal grate and no Sump; welded grates on this type can only be subjected to light traffic. Interior Dimensions 23" Wide x 42" Long x Variable Depth; Max Depth to Pipe invert is 9' 7.5". For more detail see WSDOT Standard Plans (B-35.40-00). --Drop Inlet: A trapezoidal shaped structure without a Sump. Designed with a high hydraulic capacity, these structures are effective in passing large debris. The grates of these structures are generally on grade and accept flow. --Type 2 Inlet: A round shaped structure similar to a Type 2 Catchbasin without a Sump. These structures are generally used to accept stormwater inflow through a curb opening.--Yard Drain: Round or Rectilinear structure with variable interior dimensions that are smaller than those in a Catch Basin Type 1, Type 1P, or Type 2.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/c73fd3d8e86b400aa2285c8728d31684_0engKing County GIS Open DataPublicConnect Sump and No Sump [Washington (State)--King County]Web servicesWashington (State)--King CountyWashington (State)Last Modified: 2026-01-08