San Diego officials are once again trying to convince residents that turning sewage into drinking water is not only safe but necessary for the city’s future. A recent Union-Tribune article outlines how the city’s massive Pure Water project may shift to a new method called direct potable reuse, or DPR - a process that would take wastewater, including everything flushed down toilets and drains, and purify it to a level deemed safe enough to flow directly into the public water supply.
Supporters call it innovation. Critics call it a last resort. Either way, the city is moving closer to a reality where San Diegans may be drinking water made from what they once flushed.
The Pure Water project was designed years ago as a two-phase effort to reduce reliance on imported water and bring San Diego into compliance with federal clean water laws. The first phase, using a method known as indirect potable reuse, cleans wastewater through advanced filtration and then holds it in a reservoir before it’s distributed to customers. The second phase, now under reconsideration, would skip that waiting period entirely. Instead of letting the purified water sit in a lake or aquifer for weeks or months, it would go straight into the pipes.
Officials say this change could save billions of dollars by avoiding the construction of expensive pipelines and storage reservoirs. They argue that the technology is sound, the science is proven, and that water purified through DPR can actually exceed existing drinking water standards. But this is about more than technology - it’s about trust.
The Pure Water project was designed years ago as a two-phase effort to reduce reliance on imported water and bring San Diego into compliance with federal clean water laws. The first phase, using a method known as indirect potable reuse, cleans wastewater through advanced filtration and then holds it in a reservoir before it’s distributed to customers. The second phase, now under reconsideration, would skip that waiting period entirely. Instead of letting the purified water sit in a lake or aquifer for weeks or months, it would go straight into the pipes.
Officials say this change could save billions of dollars by avoiding the construction of expensive pipelines and storage reservoirs. They argue that the technology is sound, the science is proven, and that water purified through DPR can actually exceed existing drinking water standards. But this is about more than technology - it’s about trust.
For decades, the term “toilet-to-tap” has haunted every attempt to recycle wastewater. It’s not an unfair nickname; the process literally starts with sewage. No matter how clean the final product is, public perception remains a major hurdle.
Beyond public opinion, there are practical challenges. Water use in San Diego fluctuates throughout the year, meaning the city can’t simply pump a steady flow of recycled water into the system. In the winter, when demand is low, excess purified water would still need to be stored somewhere - probably in the same costly reservoirs DPR is supposed to eliminate. City officials also acknowledge that the new system requires stricter treatment standards and more sophisticated infrastructure, which could erode the supposed cost savings.
Beyond public opinion, there are practical challenges. Water use in San Diego fluctuates throughout the year, meaning the city can’t simply pump a steady flow of recycled water into the system. In the winter, when demand is low, excess purified water would still need to be stored somewhere - probably in the same costly reservoirs DPR is supposed to eliminate. City officials also acknowledge that the new system requires stricter treatment standards and more sophisticated infrastructure, which could erode the supposed cost savings.
The Pure Water project is also coming at a steep price for ratepayers. The City Council is preparing to raise water rates by more than 60 percent and sewer rates by over 30 percent in the next four years. Officials insist these hikes are necessary to modernize infrastructure and reduce dependence on imported water, but residents will undoubtedly feel the impact. The promise of lower long-term costs is speculative, hinging on successful implementation and flawless operation of a new, largely untested system.
It’s also worth asking why sewage-to-drinking water has become the city’s chosen path when other options exist. San Diego already benefits from the Carlsbad Desalination Plant, which turns Pacific Ocean seawater into potable water. While desalination is expensive and energy-intensive, it draws from an abundant source and avoids the psychological hurdle of wastewater reuse.
It’s also worth asking why sewage-to-drinking water has become the city’s chosen path when other options exist. San Diego already benefits from the Carlsbad Desalination Plant, which turns Pacific Ocean seawater into potable water. While desalination is expensive and energy-intensive, it draws from an abundant source and avoids the psychological hurdle of wastewater reuse.
Other alternatives - like stormwater capture, graywater recycling, and stricter conservation measures - could also contribute meaningfully to the city’s water security without the same level of public discomfort. Yet those methods receive a fraction of the funding and attention being poured into Pure Water.
City leaders say this new phase of Pure Water will make San Diego a state leader in water innovation. But leading the way doesn’t always mean charging forward blindly. Direct potable reuse is still in its infancy, with California only recently approving regulations for it. Even supporters admit there are “kinks” to work out, and the long-term implications for maintenance, monitoring, and public health remain uncertain.
Other cities have already ventured into this controversial territory. Orange County has operated its Groundwater Replenishment System for years, blending highly purified wastewater into its aquifer before it’s treated again and distributed to homes - a process often praised as the gold standard for indirect reuse. El Paso, Texas, recently approved a large-scale direct potable reuse facility, while Wichita Falls temporarily used DPR during a severe drought in 2014.
There’s no denying that water scarcity is one of San Diego’s defining challenges. Imported water from the Colorado River and Northern California grows more expensive and less reliable every year. But the idea of funneling treated sewage directly into taps - however purified it may be - deserves a more robust public debate than the city seems eager to have. San Diegans have a right to understand exactly what’s being proposed, what it will cost, and how it compares to alternatives before the project moves forward.
Pure Water might eventually prove to be a model of sustainable water management, or it could become a billion-dollar experiment built on good intentions and public unease. Either way, this isn’t just about engineering - it’s about public trust, transparency, and the basic question of whether residents are comfortable knowing that what once went down the drain may soon come back through the faucet.
Internationally, Singapore’s “NEWater” program and Namibia’s system in Windhoek have successfully implemented wastewater recycling for decades, providing reassurance that with proper oversight, the process can work safely. Still, San Diego’s size, geography, and public skepticism make this a uniquely high-stakes experiment.
There’s no denying that water scarcity is one of San Diego’s defining challenges. Imported water from the Colorado River and Northern California grows more expensive and less reliable every year. But the idea of funneling treated sewage directly into taps - however purified it may be - deserves a more robust public debate than the city seems eager to have. San Diegans have a right to understand exactly what’s being proposed, what it will cost, and how it compares to alternatives before the project moves forward.
Pure Water might eventually prove to be a model of sustainable water management, or it could become a billion-dollar experiment built on good intentions and public unease. Either way, this isn’t just about engineering - it’s about public trust, transparency, and the basic question of whether residents are comfortable knowing that what once went down the drain may soon come back through the faucet.
Originally published on October 26, 2025.
