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California’s Future Water — Direct Potable Reuse

Orange County has remained an innovator in drinking water solutions for decades, even including branding the “purple pipe” to denote recycled water for irrigation.

In 2004, Garry Brown, Orange County Coastkeeper’s founder and president, was asked to participate on an oversight panel established to oversee the planning, construction, operation and monitoring of the now famous Ground Water Replenishment System. This facility was the first in the world to turn sewage into 70 million gallons per day of distilled water.

Now complete, the Ground Water Replenishment System has turned into an overwhelming success. Water professionals across the world have visited the facility and in 2008, Orange County Water District was awarded the Stockholm Water Prize – the water specific equivalent to the Nobel Prize. Since then, the facility has expanded to produce 100 million gallons of water per day.

The Ground Water Replenishment System uses an indirect potable reuse process. After going through five barriers to treatment, the water is percolated into Orange County’s underground aquifer, which acts as an environmental barrier preventing health issues from the treatment process. Later, it is pumped to the water treatment facility and introduced into the drinking water system.

Currently, the industry is evolving to direct potable reuse – a process that will shrink the environmental barrier until treated water only needs to be stored for a few hours before going to the drinking water treatment facility. This process requires revolutionary technology that must be created correctly before California can permit the facility.

In 2014, the California State Senate created by SB 918 both an expert and advisory panel to work collaboratively with the State Division of Drinking Water (now part of the State Water Board) to address the necessary criteria for permitting a Direct Potable Reuse facility in California.

Garry Brown, Coastkeeper’s founder and president, was elected to chair the advisory committee. In October 2016, the Chairs of both panels presented findings to the State Water Board. In December 2016, the State Board presented a white paper on the findings to the California legislature and the Governor. The overwhelming position is that DPR is feasible.

In 2017, the California Coastkeeper Alliance and Water Reuse California co-sponsored AB 574 (Quirk) to establish timelines for the State Water Board to develop criteria and regulation to permit the first DPR facility in California.

On December 19, 2023,  the State Water Board adopted the nation’s first comprehensive Direct Potable Reuse regulations. With guidelines now in place, California can hope to see new DPR projects in the coming years.