Public Meets Private in King County’s Green Experiment

County explores public-private partnerships to modernise water systems and boost performance outcomes

7 Oct 2025

King County, Washington, is assessing whether a public-private model could improve how communities finance and build green stormwater infrastructure. The county has issued a solicitation for planning and feasibility services tied to Community-Based Public-Private Partnership, or CBP3, projects expected to begin in 2025.

The initiative remains in its early planning and procurement stages. Officials aim to determine whether the CBP3 approach, typically used to coordinate smaller-scale improvements such as rain gardens, permeable pavements and green roofs, can deliver measurable environmental outcomes under a single performance framework.

The county’s study coincides with growing federal and state interest in alternative contracting and performance-based infrastructure models. Washington’s Department of Ecology has identified CBP3s as a potential tool for advancing its stormwater programme, and several local governments are seeking grant support to pilot the model.

“The CBP3 framework gives governments flexibility to plan and deliver projects faster,” said a Seattle-based infrastructure consultant. “It encourages private investment while keeping the focus on performance, transparency and long-term results.”

While such partnerships are well established in sectors such as transport, they remain relatively new in stormwater management. Federal agencies have shown interest in approaches that link payments to verified outcomes, viewing them as a way to align public accountability with private-sector efficiency.

If King County’s feasibility study confirms value, it could form a reference for other regions exploring scalable, collaborative solutions to water infrastructure challenges.

For now, officials describe the work as focused on strategy and evaluation. “We’re not just planning infrastructure improvements,” said one local official. “We’re designing a smarter, more adaptable future for how cities manage water.”