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Green Stormwater Infrastructure Mini Grants

The Problem/Barrier: We understand that for homeowners, investing in green stormwater infrastructure can be time consuming and costly, creating a barrier for would-be participants. Our goal is to work across the system, giving people the connections, tools, resources, and knowledge needed to care for our land and water.

The Solution: Green Stormwater Infrastructure Mini Grants provide up to $1,500 for landowners within the King County Wastewater Treatment Division (WTD) service area that are not eligible for other incentive programs. Up to $4,500 may be provided to income-limited landowners. Increased grant awards may be available to eligible projects in the Lower Duwamish. If you are ready to invest in green infrastructure on your property, we are here to help by walking you through the process and providing a financial tool.

Approved green infrastructure types include:

  • Rain gardens
  • Depave projects
  • Cisterns
  • Green roofs
  • Grattix

GSI Mini Grant will cover:

  1. Not more than $1,500 or not more than $4,500 for income-limited landowners (increased grant awards may be available to eligible projects in the Lower Duwamish)
  2. Not every project will be funded equally, grant amounts correlate to the projects projected environmental and community benefits

*Please note – Rain barrels are NOT eligible for GSI Mini Grants.
Cisterns and grattix must follow gallons of storage to contributing
area ratio outlined on pg. 2 of application.

Note: This link will take you to a King County webpage. Scroll down on the page until you see the interactive map and enter your address. WTD Service area (eligible area) outlined by green line on map. Please contact us if you are unable to verify your address using the provided tool. 

Steps to Apply:

We encourage you to apply with a pre-application if the project has been thoroughly planned but not yet completed. The project must be completed for us to issue grant payment. Pre-approval places a hold on the funds and holds your place in line for funding for up to 3 months and is subject to the project being completed as specified in design and budget. After that time frame, if the project has not been completed, the application will be rejected and funding will not be held for that project.

  1. Complete GSI Mini Grant Application including: Application and Agreement form, award calculation, project budget, site sketch and expense receipts. You can use our Green Infrastructure Site Plan Worksheet for your site sketch!
  2. Complete Applicable GSI Mini Grant Project Worksheets (one per project, located in Application form)
  3. Provide documentation of ownership of property in question (property tax form or printout from county records website)
  4. If you are income-limited, provide a form of income documentation (For homeowners: Meets HomeWise income guidelines or verified enrollment in a utility assistance program or food stamps. For non-profits: state or federal registration or non-profit letter of the non-profit organization status)
  5. Provide proof of project installation (registration at AND project sketch and picture)
  6. Complete GSI Mini Grant Checklist to ensure all steps have been followed

Live in Seattle and need to make some home repairs to get your property ready for your new GSI installation?
Check out the City of Seattle’s Home Repair Loan Program!

Get Started with Application:

Questions? Contact Stewardship Partners: ev(at)

This project is funded by the King County Wastewater Treatment Division.