UV Advanced Oxidation System for Direct Potable Reuse. Photo by WateReuse CA.

PRESS RELEASE: California’s Direct Potable Reuse Regulations flow into action

Press release from WateReuse California

The State Water Resources Control Board, along with WateReuse California, and dozens of water utilities, non-profit organizations, academic institutions, and public health agencies, partnered to develop Direct Potable Reuse (DPR) standards that further provides an additional tool to assist water agencies in combating climate change impacts and water reliability.

“The remarkable collaboration and dedicated leadership across California were essential to develop the Direct Potable Reuse regulations,” said Brenley McKenna, Managing Director of WateReuse California. “This achievement opens new pathways for developing a more sustainable water future for our communities.”

Micro Ultra Filtration for Direct Potable Reuse. Photo by WateReuse CA.

“Today marks the beginning of a new era of sustainability for California water resources. Moving forward, we will see a new generation of projects incorporating recycled water into water systems large and small across the state,” said Deven Upadhyay, Interim General Manager of the Metropolitan Water District of Southern California. “We know these projects will deliver safe, high-quality water, thanks to the decade-long efforts of the State Water Resources Control Board and many other dedicated experts to ensure these new regulations protect public health. That is our highest priority.”

Potable reuse is a proven process where water treated at reclamation facilities is further purified to above drinking water standards before being reused as a drinking water source. Two types of potable reuse options exist, Indirect Potable Reuse (IPR), and DPR.

IPR uses recycled water (often used to irrigate athletic fields, golf courses, and parks) and further treats it, using proven technology, in a three-step process called a “treatment train.” This process implements micro filtration/ultra filtration, reverse osmosis, and ultraviolet light/advanced oxidation to achieve “pure water”. Once treated, IPR uses an environmental component such as groundwater injection, reservoir augmentation, or distribution to a river above a municipal intake downstream. The water is then treated an additional time before being sent to homes, businesses, or manufacturing facilities.

DPR also uses recycled water and the same treatment train processes but does not use an environmental component. The difference exists in the increased pathogen removal efficacy and the additional monitoring requirements. The effectiveness of the treatment process is measured in “log” removal. IPR typically requires a log removal (one log is 90%, two log is 99%, and so on) of 12, which is a 99.9999999999% removal rate of all contaminants including viruses, bacteria, protozoa, PFAS, micro plastics, pharmaceuticals, personal care products, and more.

DPR has a log removal of 20 or 99.999999999999999999% of all contaminants. This increased removal rate provides additional safeguards by ensuring the DPR water is of the highest quality and safe for consumption.

Reverse Osmosis System for Direct Potable Reuse. Photo by WateReuse CA.

“Water reliability is critical to the state’s economy as many sectors including manufacturing, agriculture, residential, environmental, and local businesses use this resource to ensure their viability and success. These are the hidden uses of water,” said David Pedersen, General Manager of Las Virgenes Municipal Water District and past President of WateReuse California. “DPR, along with continued conservation efforts, gives the industry an additional reliable, safe, and resilient water source where these economic drivers can have more certainty that their water usage needs will be met.”

Climate change impacts have required water agencies to further diversify their water portfolios to ensure long-term water reliability throughout the state. Erratic weather patterns cause uncertainty for consistent snowpack and the delivery of water from northern California to the south. While IPR is more widely used, the DPR regulations provide another option for water agencies who may not have access to an environmental component and have limited source water supplies.

“WateReuse California applauds the State Water Board for its leadership and collaboration at this pivotal moment. WateReuse California partnered with the State Water Board and diverse stakeholders for over a decade to arrive at this point,” said Roger S. Bailey, General Manager, Central Contra Costa Sanitary District and current President of WateReuse California. “This is a critical component of Governor Newsom’s Water Supply Strategy which is on a path to ensure California has a sustainable supply of water to meet its demand for generations to come.”

Mother Nature has been recycling and reusing water for billions of years. The potable reuse treatment processes use the blueprint of the natural water cycle but expedite the purification of the water. These new DPR regulations are the culmination of a multi-industry effort where public health, safety, and strict compliance mandates affords California an additional option to support and ensure the critical water needs of residents and the economic foundation of the fifth largest economy in the world.

“The Pure Water San Diego program would not be possible without the continued evolution and expansion of potable reuse regulations in California,” said Juan Guerreiro, Director, City of San Diego Public Utilities Department. “The new DPR regulations provide clear regulatory pathways for future potable reuse projects, allowing substantial flexibility for individual projects while also setting rigorous standards to ensure the health and safety of public water supplies.”

WateReuse is the only trade association that focuses solely on advancing laws, policy and funding to increase water reuse. Our niche strategy sets us apart from other organizations in the water industry. Be sure to follow us on Facebook, https://www.facebook.com/WateReuse/, on X,   https://x.com/WateReuseAssoci, and LinkedIn, www.linkedin.com/company/watereuse-california/

More information on the DPR regulations: Summary of Major Provisions