It's an important topic indeed. I did a quick research a while ago and what I found is shocking.

"Water covers about 71% of the earth's surface. 97% of the earth's water is found in the oceans (too salty for drinking, growing crops, and most industrial uses except cooling). 3% of the earth's water is fresh. 2.5% of the earth's fresh water is unavailable. 0.5% of the earth's water is available fresh water" — usbr.gov

Imagine if the amount of money that goes into war is used to develop new ways to treat water.