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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. 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

King County WTD Service Area Interactive Mapping Tool


Verify that your within the King County Wastewater Treatment Division service area using the online interactive mapping tool (service area outlined by green line). Please contact us if you are unable to verify your address using the provided tool. 

Steps to Apply:

  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


Green Stormwater Infrastructure Mini Grant will cover:

  1. Not more than $1,500 or not more than $4,500 for income-limited landowners
  2. Not every project will be funded equally, grant amounts correlate to the projects projected environmental and community benefits


Get Started:


Questions? Contact Stewardship Partners:; 206-292-9875

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