Californians are acutely aware that water is a valuable and scarce resource and are concerned about protecting its quantity and quality. Irrigated agriculture, the states biggest water user, depends on good-quality water; it also degrades the quality of the drainage water. Supplying irrigation water and disposing of drainage water account for a significant part of our fossil energy consumption. Furthermore, even though irrigated agriculture is crucial to the economy and makes a substantial contribution to supplying the worlds need for food, it must compete with other demands—municipal, industrial, and recreational. The question, then, is what can be done practically to conserve water, in quantity and quality, while maintaining a viable irrigated agriculture.