Grey Water: Agricultural Use of Reclaimed Water in California

Abstract

Potential for use of recycled water1 is great, especially for agricultural irrigation, which comprises by far the highest percentage of water taken from developed sources in the arid and semi-arid regions of the world. In California, 80% of developed water is used for agriculture, and the same pattern prevails throughout the western United States. The potential for recycled water use in agriculture remains underrealized because of numerous impediments. Understanding how the incentives and impediments to agricultural reuse vary based on local context is critical to understanding the tradeoffs and technology requirements for different end uses of recycled water. Public perceptions about the safety of reclaimed water (from human waste) were a major impediment to water recycling until recent years. Several pioneers of water recycling have demonstrated—as specialists in the field of social psychology have hypothesized— that these attitudes are ephemeral and can be changed with proper outreach, demonstration, and education. Another impediment is the regulatory structure in some states. Water rights issues are another impediment specific to some western states in the United States. Cost differences for delivered water from traditional sources versus recycled water can be another challenge potentially requiring financial incentives in the interest of the greater good. One other impediment to the use of recycled water for agricultural irrigation is competition with other demands for the same water—landscape, golf course, industrial, and potable reuse. Potential for increased use of recycled water is great if impediments are removed and incentives are provided at the local, state, and/or federal levels to close the gaps (geographic and otherwise) between the utilities and the farmers.