There is also another aspect called "Water Wars". I believe this has been around since about the early 90s, when theorist predicted said events.
Apparently nations will fight for water rights or for water itself in the future. Especially in places like Africa and whatnot but expect wars to break out also in Middle East and Asian places.
Aside from that lots of people are buying water rights. I recall T.Boone Pickens being a big money baller in the water industry selling bottled water. There's other players in the industry selling water rights or selling bottled or water products to make a profit.
Some people believe water to be a multi-billion if not outright multi-trillion dollar industry and with water demand increasing each year it's just more profits.