Typically such reports focus on urban water supplies. The emphasis is understandable: most people live in metropolitan areas and water from their taps is what will make them sick if contaminated. But most freshwater is actually used by agriculture--almost 70 percent, according to the U.N. Food and Agricultural Organization. Just 12 percent goes to direct human consumption: drinking, cooking, washing, and so on. (Industry takes the rest.) For most of human history, agriculture's overwhelming thirst didn't matter; water was plentiful enough for all. But now populations have risen enough that the requirements of families and the requirements of agriculture are colliding. The water problems of cities and agriculture