Establish a global Water Investment Blended Finance Facility (WIBFF) that deploys public capital ($50B seed from multilateral development banks and sovereign wealth funds) to absorb the first-loss tranches of water and sanitation projects, enabling impact investors to fund mid-tier assets that would otherwise be unfinanceable.

The facility has four components: (1) First-loss tranches that absorb 15-20% of project risk, making junior equity returns attractive to institutional investors. (2) Subordinated loans that bridge the gap between first-loss and investment-grade returns.

(3) A Water Sector Technical Assistance Fund ($5B) that pays for feasibility studies, business plan development, and institutional strengthening for projects that haven't yet reached financial closure.

(4) Results-based financing tied to actual service delivery improvements (connections made, water quality achieved, tariff collection rate, maintenance spend) rather than asset creation. The WIBFF would be capitalized by a combination of G20 sovereign contributions, philanthropic capital, and climate finance that currently lacks clear investment vehicles.

Conservative estimate: every $1 in public capital deployed can mobilize $8-10 in institutional investment, unlocking the $400-500B annual WASH investment gap.