Blue Gold: World Water Wars [film]

"Wars of the future will be fought over water as they are over oil today, as the source of human survival enters the global marketplace and political arena. Corporate giants, private investors, and corrupt governments vie for control of our dwindling supply, prompting protests, lawsuits, and revolutions from citizens fighting for the right to survive."

There's also a documentary called "FLOW: For the Love Of Water" (watch full movie here) that came out around the same time as Blue Gold, but Janet Smith calls that one more alarmist and unorganized and Blue Gold much more informative and useful, so that's why that one is here.