THE first rule for staying alive in a desert is not to pour the contents of your water flask into the sand. Yet that, bizarrely, is what the government has encouraged farmers to do in the drought-afflicted south-west. Agriculture accounts for 80% of water consumption in California, for example, but only 2% of economic activity. Farmers flood the land to grow rice, alfalfa and other thirsty crops. By one account, over the years they have paid just 15% of the capital costs of the federal system that delivers much of their irrigation water. If water were priced properly, it is a safe bet that they would waste far less of it, and the effects of California’s drought—its worst in recorded history—would not be so severe.