Global water

Four nations, four regulatory systems, three ownership models and a rainfall gradient that puts the water in the north west and the people in the south east.

Scarcity is rarely about how much water exists. It is about timing, distribution, quality, infrastructure and governance — physical shortage is only one of five ways to run short.

The global picture, the service ladder that defines it, and why "access to improved water" and "safely managed water" describe very different situations.