GSI Implementation

In order to meet the goals set out in Green City, Clean Waters, and satisfy state and federal regulations, GSI is planned, designed, constructed, and maintained in different ways across the city.

GSI Strategic Framework

An updated strategy for what we need to manage, along with where and how to achieve our ambitious goals.


PWD Capital Projects use PWD capital funds to build different GSI tools on City-owned property and within the public right-of-way (ROW), including in sidewalks and streets. PWD’s GSI Planning & Design group coordinates these projects with other City agencies, local neighbors, and within PWD to plan, design, build, and maintain these systems.

Public-Private Partnerships

These partnerships utilize different mechanisms to plan and build GSI that connects public and private areas. These agreements between PWD and private property owners or developers can be site-specific or dependent on PWD goals in certain areas. Most of the time, these will be initiated by PWD (other than the Stormwater Grant Program).

  • Easements
  • Purchase of Assets Agreement
  • Connection to Public System
  • Development Right of Way Incentive (a Development Incentive to manage public street runoff on private property)
  • Stormwater Grants Program (eligible projects may manage public street runoff on private property)
  • Stormwater Connect (a tool to help property owners and stormwater retrofit vendors find each other)

Stormwater Regulations

The Department’s Stormwater Regulations require applicable development projects to install stormwater management practices on-site as part of the project’s construction and maintain those systems for long-term functionality. GSI is installed City-wide through development projects to comply with these Regulations.

Development Incentives

These incentives are for developers who manage stormwater runoff in vegetated systems or where systems can manage more runoff than what is required to meet the applicable Stormwater Regulations.

  • Green Roof Density Bonus (PWD and L&I)
  • Overlay Zoning Height Bonuses (PWD and L&I)
  • Tax Credits (Revenue)

Other Programs

Rain Check Program (PWD & PHS) for residential property owners interested in managing stormwater runoff.

Stormwater Credits Program for non-residential property owners who have favorable site conditions or built GSI for managing stormwater runoff.

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