ost of us think very little about water knowing mostly that it comes in two types: salt and fresh. For instance few people seem to realize that water covers over 70% of the earth’s surface and 97% of it is salt. Two per cent is frozen into glaciers and icecaps, although much of that is rapidly melting. Only 1% is liquid and drinkable, and half of that comes from below the earth’s surface. Somewhere in our memory we may remember high school science where we learned water has two hydrogen and one oxygen atoms, and is written H2O. We know water is crucial for life. How could it be otherwise: up to 60% of the human body is water, the brain is composed of 70% water, and the lungs are nearly 90% water. Lean muscle tissue contains about 75% water by weight; body fat contains 10%, and bone is 22% water. About 83% of our blood is water. Each day humans must replace 2.4 l/2.5 quarts of water, some through drinking and the rest taken by the body from the foods eaten. It is technically possible, and the lifeaffirming option to see that every person on the planet has access to at least five gallons a day for health and proper sanitation. The reality, however, is rather different. In much of Africa, Asia, and Latin America, people make do on less than a gallon a day. In contrast, in the United States, and most of Europe we use 13 gallons of water just flushing the toilet. I wrote my first essay on water in these pages in 2007, and said there “Water