Executive summary Water infrastructure lies at the centre of the world’s economic and climate resilience. To deliver equitable, resilient, sustainable and technologically advanced drinking water and sanitation systems for all, global spending will need to double by 2040. The total investment required amounts to €11.4 trillion ($13.2 trillion), revealing a financing gap of about €6.5 trillion compared with current trajectories. Bridging this gap could generate €8.4 trillion in additional GDP and support more than 206 million full-time jobs worldwide by 2040, equivalent to 14 million jobs each year. The investment gap is determined by four structural drivers of demand that together define the transformation agenda for the global water sector. One, equitable access, the imperative to extend safe and affordable water to more than 2 billion people and sanitation to over 3 billion who still lack basic access. Two, infrastructure resilience, focused on modernizing ageing and inefficient assets that globally lose about 30% of distributed water and strengthening infrastructure to protect nearly 4 billion people from climate- related shocks. Three, circularity, advancing energy efficiency, pollution control, and, more importantly, water reuse, which today accounts for only 12% of global freshwater withdrawals. Finally, innovation to close the innovation gap by deploying digital tools, automation and artificial intelligence. Circularity and innovation hold the key to transforming water systems from linear to circular, in which every drop is reused, every discharge repurposed, and resilience becomes inherent to the way the sector creates equitable access. Encouraging examples from leading corporations and countries presented in this paper demonstrate that progress is both possible and replicable. The challenge is therefore not invention but scaling, sharing best practices, raising awareness about them and adapting them to local realities. Delivering resilient and investable water systems will depend on four enablers that act in concert rather than sequence. Policy reform should establish coherent national water strategies, align tariffs with the real cost of service and improve coordination and data transparency to reduce water usage, improve efficiency of use and boost reuse, as well as bankability. Financial innovation, through instruments such as blue bonds, blended finance, and performance-based public-private partnership (PPP) and regulated asset base (RAB) models, can mobilize private capital when supported by public guarantees and development finance. Technology adoption should focus on creating a stimulating environment to accelerate research and development and venture capital investement, while ensuring that proven solutions are implemented and scaled without delay. Finally, cultural transformation is essential: building a culture of water stewardship through education and professional training ensures long-term behavioural change and societal engagement. These enablers are not ends in themselves; they form the toolkit that allows governments, investors and industry leaders to translate ambition into execution. Closing the global water infrastructure gap is achievable, but it requires coordination and leadership. Governments should position water as a strategic asset in national priorities, creating predictable frameworks, boosting efficiency and reuse, and deploying strategic public capital or guarantees to attract private investment. Industry leaders should pursue operational excellence, circularity and measurable outcomes that enhance project bankability, while financiers can expand the use of innovative instruments and consider treating water as a separate asset class to channel capital towards. This paper does not offer a single prescription, but rather a menu of proven best practices – adaptable, replicable and ready to scale. With coherent policy, innovative finance and technology deployed through partnership, water can evolve from a constraint into a catalyst for sustainable growth, infrastructure resilience and equitable access. The tools are available; what is needed now is decisive and collective action to deploy them at scale.Coordinated action across government, industry and finance is needed to close a €6.5 trillion water infrastructure gap. Bridging the €6.5 Trillion Water Infrastructure Gap: A Playbook 5

Bridging the 6.5 Trillion Water Infrastructure Gap A Playbook 2025