You don't miss the water 'til the well runs dry!!

Breaking Down the Water Supply
Water is a common chemical substance, essential to all known forms of life. About 1,460,000,000,000,000 (1,460 trillion) tons of water covers 71% of the Earth’s surface, but relatively little is suitable for consumption. In many parts of the world, suitable water is in very short supply.

Let’s scale the world’s water supply to a size easier to comprehend like 58 gallons, about the same as a really full bathtub.

55 gallons of that water is saltwater ocean.
About 10 pounds of ice is locked in polar ice caps and glaciers.
About one drop is in the atmosphere as vapor, clouds, and precipitation.
Another drop is in our soil, and part of life itself (our bodies are made up mostly of water, for instance).
Our water sources:
Almost one gallon of that water is below ground in aquifers.
About four tablespoons is in surface water such as rivers and lakes.
Three-fourths of this is polluted or otherwise unavailable to us.
We are left with less than a liter of this water to live on.

Here are a few good books on the subject of water: Water The Fate of Our Most Precious Resource by Marq De Villiers, Water A Natural History by Alice Outwater, Pillar of Sand by Sandra Postel, When the Rivers Run Dry by Fred Pearce, Ogallala Water for a Dry Land by John Opie, Cadillac Desert by Marc Reisner, Water Follies by Robert Glennon, and Ogallala Blue by William Ashworth.

Someday soon the subject of water will be more important than oil.