California recently became the third state in the nation to approve using recycled wastewater for drinking water. After ten years spent developing regulations for direct potable reuse (DPR), the California Water Resources Control Board voted to approve the use of DPR within the state, a decision that came just shy of a December 31, 2023 deadline.

For decades, California has allowed the use of recycled water to make ice for ice rinks, snow for ski resorts, and to irrigate crops. Gaining approval to use it for drinking water increases water resilience and represents a change in public opinion as the state strives to find reliable water sources for its nearly 40 million residents.

The approval allows for DPR but does not mandate its use across the state. Due to the cost associated with the process, it will likely be utilized only by larger municipalities at the onset, some of which are already developing the process. The Metropolitan Water District of Southern California plans to recycle as much as 150 million gallons per day with the goal of providing close to half of San Diego’s water through recycling by 2035.[1]  

To ensure the safety of DPR water, policymakers outlined detailed rules for “controlling and monitoring chemicals and pathogens, as well as comprehensive instructions for plant operations, maintenance and compliance,” assuring “triple redundancy” in the regulations.[2]

Although approved, the new regulations won’t go into effect until they are accepted by the state’s Office of Administrative Law, likely by the summer or fall of 2024.[3]

[1] Beam, Adam; Bloomberg. “‘Toilet to Tap’: California Approves Using Recycled Wastewater for Drinking to Help Solve Frequent Drought.” Fortune, Fortune, 20 Dec. 2023, fortune.com/2023/12/19/california-oks-new-rules-wastewater-drinking/.

[2] Udasin, Sharon. “California Regulators Adopt Wastewater Reuse Rules, Knocking ‘toilet-to-Tap’ Misnomer.” The Hill, The Hill, 19 Dec. 2023, thehill.com/policy/equilibrium-sustainability/4368209-california-regulators-adopt-wastewater-reuse-rules-knocking-toilet-to-tap-misnomer/.

[3] Becker, Rachel. “California Approves Rules That Turn Sewage into Drinking Water.” CalMatters, 19 Dec. 2023, calmatters.org/environment/2023/12/california-rules-turn-sewage-into-drinking-water/.