California water reuse—Past, present and future perspectives

The State of California has a long history of water reclamation and reuse and in 1918 developed the first regulations in the United States to address the use of recycled water for agricultural irrigation. In California, as well as in many water-scarce areas, water reclamation, recycling, and reuse are integral components of water resource planning and management. Historically, the driving motivation for water recycling was to supplement scarce resources and to provide alternatives to effluent disposal into surface waters. The California State Water Resources Control Board (State Water Board) adopted a Recycled Water Policy that moves towards the sustainable management of surface waters and groundwater, together with enhanced water conservation, water reuse, and the use of stormwater. In California, the practice of planned potable reuse has occurred in the form of indirect potable reuse (IPR), including an environmental buffer, for over 50 years. California's experience has demonstrated that planned potable reuse using IPR can be practiced without having any apparent detrimental effects on public health. In 2018 the State Water Board adopted surface water augmentation regulations(1) that establish minimum uniform water recycling criteria for he planned placement of recycled water into a surface water reservoir that is used as a source of domestic drinking water supply. The transition from IPR to direct potable reuse has the potential to modify conventional public health practices by removing the environmental buffer between wastewater disposal and water supply. California is currently developing regulations that would govern potable reuse situations that have either no environmental buffer and/or a reduced buffer.