Water: Better the second time around

California's growth and recurring droughts have continued to increase demand on the state's drinking water supplies. In early 2008, the regional groundwater management authority for central and north Orange County, California, began operation of the world's largest recycled groundwater recharge project. Utilizing domestic wastewater as the supply, approximately 70 millions gallons per day of highly treated recycled water is directly injected and surface spread in order to supplement the natural recharge of the regional aquifer system. The aquifer system provides over 2 million Orange County residents with about two-thirds of their drinking water supply. The Groundwater Replenishment System project faced many public health questions from the state and local health agencies, including the long term consequences of exposure to trace chemicals and emerging contaminants in drinking water derived from groundwater recharged with recycled water. To address these questions, significant health related water quality research was conducted by the regional groundwater authority. The State of California's Department of Public Health Groundwater Recharge Draft Regulations were developed using much of the research conducted for this project. Project regulatory criteria included multiple barrier treatment processes to mitigate microbial, pharmaceutical and trace organic chemical contaminants. Additional criteria included comprehensive water quality monitoring, a wastewater source control program, an independent advisory panel, public outreach and education, and minimum residence time in the aquifer before use for drinking water supplies. This presentation will examine the public health challenges associated with the project, how they were mitigated and recommendations for future projects.