This article addresses the need to profoundly expand the way we think about freshwater. Stressing water's role as the bloodstream of the biosphere, the article highlights water's functions in sustaining life on the planet (control, state and moisture feedback functions), the role of water partitioning changes in inducing non-linear change at multiple scales, and humanity's influence on a social-ecological system's capacity to adapt and continue to function. It reviews water's roles during its journey through the upper layers of the land mass, different types of water-ecosystem interactions, and water's roles in landscape-scale resilience building.