Pure Water San Diego - Potable Water Reuse Program

Pure Water San Diego, is the City of San Diego, California’s phased, multi-year sustainability program that intends to provide one-third of San Diego's water supply locally by 2035. The Pure Water Program will use proven water purification technology to clean recycled water to produce safe, high-quality drinking water. Environmental stressors and climate change impacts, such as ongoing drought in the Colorado River Basin, and reduced snowpack and runoff in Northern California have decreased the availability of local water supplies, and San Diego has turned to investing in adaptive alternatives.

The Pure Water facilities are planned in locations throughout San Diego, and are grouped into three geographical areas to facilitate implementation: North City, Central Area and South Bay. Construction on the Phase 1 projects will start in 2019 - and by 2035, the program will allow the City to produce 83 million gallons of purified water every day, and the purified water will be distributed to all communities in San Diego.

The Pure Water Program:

  • Uses proven technology to clean recycled water to produce safe, high-quality drinking water
  • Provides a reliable, sustainable, water supply
  • Offers a cost-effective investment for San Diego’s water needs

The water purification process includes five steps: ozonation, biological activated carbon filters, membrane filtration, reverse osmosis, and ultraviolet disinfection with advanced oxidation. In order to determine that the purifying recycled water is safe, the City conducted a demonstration project (2009-2013) that confirmed the purified water meets all federal and state drinking water standards.

The program development process is described in the American Water Works Association article: “Potable reuse: Developing a new source of water for San Diego.” The article details the original potable reuse study which began in 2006, project testing results, regulatory coordination, energy and cost analysis, and the ultimate support of the City Council in 2013. 

As described in this article - with San Diego’s existing water system, only 8% of the wastewater leaving homes and businesses is recycled; the rest is treated and discharged into the ocean. In addition, “San Diego relies on importing 85% of its water supply from the Colorado River and Northern California Bay Delta. The cost of this imported water has tripled in the last 15 years and continues to rise."



Publication Date: 2013

Related Organizations:

  • City of San Diego, California


Resource Category:

Resource Types:

  • Best practice

States Affected:


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