Fresh water already is a limited commodity in some areas of the world. You might recall when the city of Atlanta came close to running out of water — about 10 years ago.
Now see this article, We Have Seen The Future Of Water, And It Is Cape Town. It describes how close that city is to running out of fresh water today.
Israel is held up as an example of conservation and the desalinization of sea water. This is a technological solution, but not available to everyone due to the cost.
I figure, like everything else, it will take a crisis of epic proportions before we address water shortages here in the United States. It takes a crisis before we are able to move ourselves to action.
Claire Rubin shared the link above.