Though Earth’s surface is some 70% water, less than 3% of all that is fresh — and even less is drinkable on any given day. With the world’s population on the rise and local water supplies shifting, we’re going to need to change the ways we create and consume fresh water.

In honor of World Water Day, Fw:Thinking explores how we might purify and desalinate what we have — and how asteroids might be the aquifers of the future.