San Diego County’s “As a result of population growth, urbanization, and climate change, public water supplies Water Supply Diversification are becoming stressed, and it is getting more difficult—if not impossible—to tap new water supplies for metropolitan areas. So existing water supplies must go further. One The San Diego County Water Authority Imperial Irrigation District, the Water Authority way to do this is to increase water reuse, particularly in supplementing municipal water provides a safe and reliable water supply to will receive highly reliable Colorado River 24 member agencies in the San Diego region water for decades to come. The Water supplies by means of direct or indirect potable reuse.” andand its its 2424 member agencies agencies serving 3.2 million residents and an annual Authority is receiving additional conserved economy of more than $200 billion. The water from projects that lined sections of the Source: George Tchobanoglous, expert in water reuse and a professor emeritus at the University of California, Davis Water Authority and its member agencies are Coachella and All-American canals. executing a long-term strategy to diversify water sources, invest in the region’s water Many Water Authority member agencies delivery and storage system, and improve currently deliver recycled water for non- water use efficiency. potable irrigation and industrial uses. Ground- water is a small but important local water This strategy began as a result of a severe supply source, and some member agencies multi-year drought that peaked in 1991, when are expanding use of the region’s groundwater the San Diego region was 95 percent reliant aquifers through conjunctive use, ground- on the Metropolitan Water District of Southern water replenishment and brackish ground- California and faced major cutbacks. Since water desalination. The Water Authority is then, the San Diego region has cut its reliance also tapping the ocean as a highly reliable on MWD in half. source of local supply. The completion of the Carlsbad Desalination Project is projected The Water Authority and its member agencies to provide 56,000 acre-feet of drought-proof have proactively pursued water use efficiency water annually. Purified water projects de- since the early 1990s. The Water Authority veloped by Water Authority member agencies provides education, incentives and support are expected to be an important future water for changes in standards to transform how supply. For more information about the Water we use water. The Water Authority also has Authority’s efforts to enhance our regional invested in Colorado River water conserva- water supply reliability, please visit sdcwa.org/ tion and transfer agreements. By supporting enhancing-water-supply-reliability. increased agricultural water efficiency in the

1991 2035 chart shows 2014 2035 diversification of San Diego County’s water resources, including the maximum potential supply from Total = 578 TAF purified water projects being considered by member agencies. Purified Water’s Role in San Diego County’s

Total = 667 TAF Total = 959 TAF

and its 24 member agencies Metropolitan Water District Conservation Groundwater sdcwa.org/purified-water Imperial Irrigation District Transfer Recycled Water Local Surface Water

Potable Reuse (Conceptual All American & Coachella Canal Lining Seawater Desalination and planned projects) WATER SUPPLY @sdcwa

Thousand Acre-Feet (TAF) 4677 Overland Avenue, San Diego, CA 92123 • (858) 522-6600 Purified water is going to play an Purified water is a local, reliable, drought-proof Understanding the important role in our water supply future water source and provides vital benefits Water Purification Treatment Process

Safe, reliable option for increasing water supply — Purified Currently, most advanced water purification processes involve water uses proven technology that cleans water to a level that a multi-stage process of micro-filtration, reverse osmosis, and tests cleaner than most bottled water. ultraviolet light with advanced oxidation. Sustainable, drought-proof water supply — Having a safe, sustainable water supply ensures water is available even during periods of drought and in response to changing climatic “The California Medical conditions. Association encourages Proven technology — Hundreds of thousands of Orange County efforts to expand potable homes and businesses receive advanced purified water for reuse and non-potable drinking and other uses, including the nearly 15 million people Purified Water Provides a that visit Disneyland every year. Safe Supply of Water water reuse; conserve Step 1: To purify recycled water, the first step is to pretreat the water through micro-filtration. Water is pumped through tubes filled with tiny Purifying water for reuse, also referred to as water, monitor recycled The diagram below shows the water purification and recycled water membranes. Each membrane, made up of hollow fibers, is perforated potable reuse, employs advanced multi-barrier processes and how the water is used in our community: water quality, and with holes 1/300th the width of a human hair. Through this process, treatment technology to purify water to safe solids and bacteria are caught in the fibers and removed from the water. drinking water quality levels. This separates encourage source pollutants from the water, purifying it to a reduction of contami- drinking water level that fully complies nants; and encourage with both federal and state drinking water Reusing Water is Your home standards. Purified water is continuously Good for the Environment private and public tested and is monitored by the State of California Division of Drinking Water. Not only is it important for the Water Authority cooperation to further and its member agencies to provide a reliable develop technologies source of high-quality water to its residents Advanced The recycled water and businesses, it is also a priority to develop and programs to Wastewater puri cation Puri ed water a strategy that is environmentally responsible. increase water treatment plant facility Step 2: The water is treated through reverse osmosis, a process is now purified Reusing water means less water is removed that again forces the water through membranes, removing salt, from lakes, rivers and streams. These surface reuse while ensuring micro-organisms and chemicals. Recycled water to a level that is water supplies are a critical source of water for water quality.” wildlife, fish and plants. cleaner than most Purifying water for drinking also reduces Resolution on water recycling adopted Groundwater Reservoir wastewater discharge into the ocean. by the California Medical Association, Padre Dam Municipal Water District November 2012 bottled water and Agriculture Landscape Industrial Locally Sourced Water Ensures Stability is ready to drink. As water resources are being stressed around the state, it is critical for the San Diego region Step 3: At this point the water is purified, but will go through one more to continue its strategy to diversify water supply Drinking water step to ensure safety. The treated water is exposed to ultraviolet light sources and to rely less on imported water. treatment with advanced oxidation causing any remaining organic chemicals to Your home Purifying water is a cost-effective option that break down into simple elements such as oxygen, nitrogen and carbon. will provide a locally controlled, drought-proof water supply that is safe and reliable.