Its not just water, but the quality of water that is important, you have no idea how many people in the world die from water they drink that has bacteria and parasites in it. Some rich countries like Saudi Arabia get most of their water from huge Reverse Osmosis water plants (turns salty sea water into pure water for drinking and irrigation), without it that country would fall apart in a few weeks. Asia is the big place for water wars. India, Vietnam, China and the other countries in that area that get their water from Mountain runoff are going to have major issue now that rivers are going dry and China is damming them all up. Billions of people in that area are going to be in big trouble, heck we have water issues in over half the country here and it will get worse.