Industrial use takes about 60% of water in rich countries and 10% in the rest. The difference in domestic use is much smaller, 11% and 8% respectively. Some of the variation is explained by capacious baths, power showers and flush lavatories in the rich world. All humans, however, need a basic minimum of two litres of water in food or drink each day, and for this there is no substitute. No one survived in the ruins of Port-au-Prince for more than a few days after January's earthquake unless they had access to some water-based food or drink. That is why many people in poor and arid countries—usually women or children—set off early each morning to trudge to the nearest well and return five or six hours later burdened with precious supplies. That is why many people believe water to be a human right, a necessity more basic than bread or a roof over the head.