Through an innovative effort that advances Gov. Gavin Newsom’s Water Supply Strategy for adapting to a hotter, drier future, California’s regulations for converting wastewater to high-quality drinking water became official on Oct. 1 – coinciding with the first day of the new water year. The regulations clear the way for water systems to invest in innovative treatment plants and processes that will recycle – and reuse – millions of gallons of wastewater daily.
The State Water Resources Control Board unanimously approved the regulations in December 2023, giving California the most advanced standards in the nation for treating wastewater to such an extent that the finished product meets or exceeds current drinking water standards. The regulations became effective Oct. 1.
Through “direct potable reuse,” water systems will be able to generate a climate resilient water source, reduce the amount of wastewater discharged to rivers and the ocean, and add millions of gallons of recycled drinking water over time while avoiding costlier, more energy intensive water supplies.
“The official launch of these regulations affirms California is a global leader in finding innovative solutions to build a more water-resilient future,” said E. Joaquin Esquivel, chair of the State Water Board. “Not only will direct potable reuse provide millions of Californians with greater water security; our collaboration with industry partners will have a resounding ripple effect throughout the United States and beyond.”
READ: What water and environmental leaders are saying about the regulations
A panel of experts carefully examined the trove of research data on the multi-barrier treatment process that recycles wastewater into drinking water in mere hours, and it affirmed the meticulous public health protections. In the past 13 years, California has invested $24 million to fund 34 research projects that sought to identify knowledge gaps and confirm the feasibility of creating DPR regulations. An additional $2 million was invested in the final phase of regulatory development to ensure that this new frontier of water resiliency is protective of public health and environmental safety.
The DPR regulations build on the state’s long-standing and widespread use of indirect potable reuse technology for more than 60 years – a protocol that involves thoroughly treating wastewater and discharging it into a stream or reservoir or recharging groundwater used as a source for drinking water. Through this process, the treated wastewater is blended with the natural water source, which then goes through the standard treatment process to become drinking water.
The DPR regulations create new opportunities for the future of water management and resiliency. While no formal direct potable reuse projects could be initiated until the regulations were adopted, water agencies in Santa Clara, San Diego and the city of Los Angeles have launched pilot projects in recent years. The newly adopted regulations comply with California’s Safe Drinking Water Act, which ensures that the water delivered by public water systems in California shall, at all times, be pure, wholesome and safe to drink.
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