Water reuse has been an important tool in improving water supply reliability in water-scarce Southern California. Recycled water is the result of treating wastewater to tertiary standards as prescribed in Title 22 of the California Code of Regulations. Tertiary-treated recycled water is non-potable and can only be used for permitted non-potable uses, such as irrigation or industrial processes. Regionally, increasing recycled water use is a priority to reduce reliance on imported water, which is energy-intensive, subject to curtailment during droughts, and expensive. Although individual agencies have worked to increase recycled water in the Project Area, there has been a nearly 20-year history of joint water recycling efforts.
In the late 1990s, Olivenhain Municipal Water District, Carlsbad Municipal Water District, Leucadia Wastewater District, and San Elijo Joint Powers Authority worked together on the first regional recycled water project in northern San Diego County, known as the North County Recycled Water Project. This first effort, totaling approximately $133 million in expenditures, was awarded $20 million in U.S. Bureau of Reclamation Title XVI funding. The end result was 10,000 acre-feet—over three billion gallons—of recycled water that is currently being delivered to the region’s customers each year. Today, the nine-member NSDWRC Coalition has formed to further advance recycled water in northern San Diego County through the Regional Recycled Water Project. The new Project will maximize recycled water use among the agencies, develop interconnections to more efficiently distribute recycled water, and construct new water reclamation facilities to increase the supply of recycled water available to each of these agencies’ respective customers.
Recycled water makes financial sense, as well as sense from an environmental and water supply perspective. A large portion of the potable water in San Diego County is imported water. In 2013, the cost for imported water was approximately $1,200 per acre-foot, with costs projected to rise every year. In general, recycled water costs approximately 15 percent less than potable water, in large part due to the offset of imported water. For large water customers, such as certain industrial users, or large-scale irrigators (e.g. golf courses), converting to recycled water can be a substantial cost saver.
Interested in learning if recycled water is an option for you? Contact your local water supply agency by visiting our Contact page.
Potable reuse is a drought-proof, local supply that can be used to improve water supply reliability. Potable reuse is a form of water reuse in which wastewater is recycled, undergoes advanced treatment and reenters the supply system through direct or indirect means. Indirect potable reuse (IPR) involves adding advanced treated recycled water that meets all drinking water standards into a groundwater basin or reservoir where it blends with water from other sources. Direct potable reuse (DPR) involves adding advanced treated recycled water added directly into an existing potable water system, upstream or downstream of a water treatment plant.
In California, there have been a number of successful indirect potable reuse projects, including the Groundwater Replenishment System in Orange County, the West Basin Water Recycling Project (West Coast Basin Seawater Barrier) in Los Angeles County, the Montebello Forebay Spreading Grounds in Los Angeles County, and the Inland Empire Utilities Agency Recycled Water Program in San Bernardino County. Pure Water San Diego and the East County Advanced Water Purification Project are two proposed indirect potable reuse projects where advanced treated recycled will be discharged to San Diego County reservoirs and further treated at a downstream drinking water plant. These two projects have conceptual approval from the State Water Resources Control Board and are currently under construction. The projects are anticipated and are expected to be online in approximately 2023 and 2025, respectively.
In 2014, the State of California adopted regulations for indirect potable reuse via groundwater recharge (injection or surface spreading). In 2018, as mandated by Senate Bill 918 (2010), the State adopted regulations for indirect potable reuse via reservoir augmentation, which consists of adding advanced treated water to a reservoir or conveyance leading to a reservoir upstream of a drinking water plant. As there are no regulations for indirect potable reuse, minimum standards have been set for all relevant aspects of these projects, including treatment provided, effluent quality, spreading area or injection well operations, soil characteristics and hydrogeology, distance to withdrawal and/or required dilution. The State Water Resources Control Board’s amended Recycled Water Policy became effective in 2019, which among other things, updates the monitoring requirements for recycled water use for groundwater recharge and reservoir water augmentation. Use the following links to learn more about the Recycled Water Policy and Surface Water Augmentation.
The regulatory environment in California is changing to recognize that direct potable reuse, when implemented safely, is a valuable tool for meeting water supply demands. The State Water Resources Control Board is currently working on regulations for direct potable reuse, which are expected to be available in 2023. In the interim, the State will permit direct potable reuse projects on a case by case basis based on the characteristics of each project, including the treatment provided, effluent quality and quantity, reservoir or drinking water treatment plant operations, and distribution system operations.
While each individual scenario for indirect and direct potable reuse may be different, the overriding goal remains the same: produce purified water that at all times is of a quality that fully protects public health.
For more information on recycled water and the Project, download our fact sheets: