The economic development-environmental protection dichotomy is an out-dated construct. A 21st century approach to the world's water problems is progressively being developed by researchers and practitioners, who are combining traditional and ecosystem-based engineering systems to yield cost-effective solutions. Given the continuing and widespread loss of ecological services and functions, water security in a multi-generational, SDG context requires a meaningful, global commitment to redirect the current downward trajectory in both (i) the state of the world's ecosystems and the services they provide to society, and (ii) our collective level of stewardship of these important resources. Achieving sustainable water security will require overcoming strategic challenges related to protected areas, ecosystem-based solutions research, water observatories and expanded technical readiness. It also needs to address other limitations and demands related to water infrastructure, economies, human settlements and water quality, sanitation and health. Four globally significant actions can support the adoption of more efficient and sustainable water futures: green infrastructure watershed banks, an accelerated global research and solutions program, a new global water-ecosystem services observatory, and an improved technical capacity/workforce development initiative. Finally, the engagement of relevant stakeholders from academia, government, the private sector and civil society are needed to ensure that humankind will be able to meet its water security goals and commitments, including those expressed in the sustainable development agenda.