Many believe that water scarcity due to population growth and climate change would be a central factor in future conflict. For Israel specifically, it's a huge source of tension with neighbors. Here's a technological solution to prevent this. As they say: Necessity is the mother of invention.
"Israel now gets 55 percent of its domestic water from desalination, and that has helped to turn one of the world’s driest countries into the unlikeliest of water giants."
"...the national water authority built innovative water treatment systems that recapture 86 percent of the water that goes down the drain and use it for irrigation — vastly more than the second-most-efficient country in the world, Spain, which recycles 19 percent."