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Our Water Treatment Process

Water Treatment Plants

The City of San Diego has three water treatment plants that utilize several treatment processes to provide safe drinking water to the public. The plants are managed by the City's Public Utilities Department. The Department actively participates with the American Water Works Association's (AWWA) Partnership for Safe Water Program, the mission of which is to improve the quality of drinking water delivered to customers of public water supplies by optimizing system operations. To find out which of the three water treatment plants produces water for your area, see the map on the Frequently Asked Questions page.

Note: In an effort to increase and improve security, the Public Utilities Department no longer offers public tours of its water treatment plants; however, the Department does conduct public tours of some of its other facilities.

Alvarado Water Treatment Plant

Photo of Alvarado Water Treatment Plant

When the Alvarado Water Treatment Plant began operation in 1951, it replaced old water treatment plants at University Heights and Chollas Heights. Located adjacent to Murray Reservoir, Alvarado today provides drinking water to customers in the central section of the City. Plant capacity is 120 million gallons of treated drinking water per day. A multi-phase expansion and upgrade project for the plant was completed in 2011 and included a 1.1 megawatt solar power system. The Alvarado Plant began its first year of active participation in AWWA's Partnership for Safe Water Program in 2013 and has implemented several optimizing projects. Alvarado is also home to the City's Water Quality Laboratory, which continuously monitors the City's drinking water to make sure it is always safe and meets all state and federal health standards.

Miramar Water Treatment Plant

Photo of Miramar Water Treatment Plant

The Miramar Water Treatment Plant began operation in 1962. The plant provides drinking water to an estimated 500,000 customers in the northern section of the City. Located in the Scripps Miramar Ranch community, the treatment plant is adjacent to Miramar Reservoir. Plant capacity is 144 million gallons of treated drinking water per day. The City recently completed a 14-year multi-phase expansion and upgrade plant project to ensure future customer demands and more stringent drinking water standards/regulations were met. Since 2012, the Miramar Water Treatment Plant has participated in the American Water Works Association's Partnership for Safe Water Program, which involved an extensive self assessment and optimization program and report. Based on the plant's staff efforts and its documenting report, the plant was awarded the Partnership's Director's Award in November 2012. In continuing its efforts to achieve a more fully optimized system, the Miramar Water Treatment Plant was subsequently awarded the Partnership's President's Award in June 2013. Currently, there are only five other treatment plants in the United States that have achieved this prestigious award.

Otay Water Treatment Plant

Photo of Otay Water Treatment Plant

The Otay Water Treatment Plant began operation in 1914. The plant provides drinking water to an estimated 100,000 customers in the southern section of the City. The plant is located adjacent to Lower Otay Reservoir. The smallest of the City's three water treatment plants, Otay Water Treatment Plant's capacity is 34 million gallons of treated drinking water per day. In 2010, the City completed an expansion and upgrade project for the plant that included an 804 kilowatt (AC) solar power system. The City's Otay Water Treatment Plant received the Director's Award of Recognition multiple times from AWWA's Partnership for Safe Water Program. This award was obtained while treating more challenging source water quality from local reservoirs and is recognition of outstanding performance by the plant staff team.