Storm Drainage Report

Some building and utilities permits issued by the City of Bellevue require a storm drainage report to be submitted for plan review. Prepare your report using the requirements outlined in the 2017 Surface Water Engineering Standards (SWES), Section D2 - D6. For assistance in submitting your report online, refer to Electronic Plan Requirements and Electronic Review Efficiency. For questions regarding your submittal, contact the Utilities Review desk.

  • All plan sheets must be a minimum of 18 x 24 inches. 
  • Storm drainage reports must be on 8 ½ x 11 inches and should be separate from the geotechnical report.

Project Information

  • Project address
  • Name, address and stamp of preparer (if a licensed individual)
  • Vicinity map

Report Requirements

  • Table of contents.
  • Utility standards and Department of Ecology codes pertinent to the project.
  • Project overview - existing and proposed conditions.
  • One quarter mile downstream analysis.
  • Off-site capacity analysis (if applicable).
  • Site Assessment and Planning Packet
  • Pre-developed and post-developed chart showing square footage of hard surfaces and pervious surfaces.
  • Figure 1.4 or 1.5 highlighting the flow path used to determine stormwater minimum requirements for the project.
  • Highlight flow path on 2017 SWES, Figure 5.1, for infiltration feasibility.
  • Details of infiltration testing, if required (test hole must be a minimum of six feet deep per 2017 SWES Appendix D-10).
  • Discussion of how each minimum requirement is being met.
  • Thorough discussion of List #1, List #2 or LID performance standard (2017 SWES D104.2(e)). Include infeasibility criteria per 2017 SWES Table D-9.1 and D-9.2.
  • Sizing calculations for Best Management Practices (BMPs) proposed.
  • When required per 2017 SWES D4-03, provide hydrologic/hydraulic calculation methodologies, inputs, assumptions and results for analysis of off-site conveyance capacity.