King County Tests Private Help for Public Waters

Seattle-area initiative tests performance-based partnerships to expand sustainable stormwater systems

14 Oct 2025

King County, Washington, is testing a new framework for funding and delivering sustainable infrastructure, exploring how public and private sectors can better collaborate to manage stormwater and reduce pollution.

The county has begun early planning for a Community-Based Public-Private Partnership, or CBP3, a model promoted by the US Environmental Protection Agency to accelerate green infrastructure projects. The approach enables local governments to contract private partners to design, build, finance, and maintain stormwater systems under long-term, performance-based agreements.

Instead of paying only for construction, agencies compensate partners based on outcomes such as how effectively systems capture or treat runoff. County officials say this model could help deliver more projects, faster, while maintaining environmental standards.

King County’s 2025 solicitation for “Planning Services for the CBP3 for Stormwater Retrofits Project” marks the initiative’s first phase. The work will define the programme’s structure, financing, and oversight mechanisms. Implementation has yet to begin, but the county hopes its findings will guide other jurisdictions exploring similar strategies.

“CBP3s allow local governments to leverage private-sector innovation while maintaining public oversight,” said a senior county adviser. “It’s about aligning incentives to deliver cleaner water and stronger communities.”

Interest from private firms is growing. Large infrastructure and consulting companies are monitoring the county’s progress, seeing potential to expand into performance management and long-term maintenance.

However, challenges remain. Measuring hydrologic performance requires sophisticated data systems and clear verification methods. Cities may also need to adapt procurement rules to enable results-based contracts. “The challenge will be ensuring performance metrics are transparent and verifiable,” said an analyst at Bluefield Research. “Without clear data, accountability could falter.”

With climate pressures rising and public funding stretched, King County’s CBP3 effort represents a cautious test of whether performance-driven partnerships can help cities build more resilient, sustainable infrastructure.