Proposed Inlets

This layer displays all the catch basins, catch basin grated tops, sandboxes, junction boxes, inlets and trash racks within the City of Seattle (and the former service area north of the City limits) regardless of ownership.

A catch basin is a connector to the storm drain system that typically includes an inlet where stormwater enters the catch basin and a sump to capture sediment, debris, and associated pollutants prior to the surface water flowing into a storm or sewer pipe. There are two main types of inlets: side inlets and grated inlets. Side inlets are located adjacent to the curb and rely on the ability of the opening under the curb to capture flow. Grated inlets have gratings or metal grids to prevent large objects and debris from falling into the combined sewer or drainage system. They collect surface runoff for conveyance in a pipe system. Sandboxes have wooden lids and are filled with sand or gravel and drain directly into the ground or to a culvert as part of the informal drainage system. Sandboxes are no longer being installed. Junction boxes are cement structure with a grated metal lid, shallow in depth, generally connect culverts and are inline as part of the informal ditch and culvert system. Trash racks are grated structures that collect debris. Trash racks may be on maintenance holes, catch basins, other structures, or streams.

Data source is DWW.catch_basin_pt_pv, and DWW.APPURTENANCE_PT_PV. Maintained by SPU GIS DWW Data Maintenance staff. This layer does not display when zoomed out beyond 1:899.

Refreshed daily.
Organization: City of Seattle
Last updated: 2025-02-28T23:50:07.010460
Tags: appurtenance-point, catch-basin, catch-basin-grated-top, cb, cbl, inl, inlet, jb, jbs, junction-box, junction-box-with-sump, sandbox, sb, seattle-gis-open-data, trash-racks, trr