The rainwater and wastewater recycling project currently under construction beneath the Santa Monica City Hall parking lot marks a significant advancement in California’s approach to water sustainability. As reported by LAist, the state has officially entered a new era of water recycling, which was once met with skepticism and labeled by critics as “from toilet to tap.” The newly enacted regulations allowing “direct potable reuse” mean that wastewater—essentially water flushed down toilets or draining into sewers—can now be processed to drinking standards and distributed directly to households and businesses.
Mickey Chaudhuri, Manager of Water Quality at the Metropolitan Water District (MWD) of Southern California, emphasized that this regulation provides MWD and other water agencies with greater flexibility in addressing the extreme variations in rainfall caused by global fossil fuel pollution. “We can enhance our supply, whether in droughts or wet years, by relying on recycled water to better cope with extreme climate conditions,” he stated.
Southern California has been at the forefront of using recycled water for over 15 years, particularly for irrigating parks and golf courses. The Orange County Water District has been a pioneer in promoting safe methods for drinking recycled water. Previously, California laws only permitted “indirect potable reuse,” which involved injecting highly treated wastewater into underground aquifers for further natural filtration before it entered the drinking supply. The new law streamlines this process by allowing highly treated wastewater to flow directly into drinking water treatment facilities.
The climate crisis is exacerbating water supply instability, with California projected to lose 10% of its traditional water supply by 2040—more than the full capacity of Lake Shasta, the state’s largest reservoir. Increasing the use of recycled water is one strategy cities in Southern California are employing to reduce dependence on the increasingly unreliable sources from the Colorado River and snowpacks in the Sierra Nevada.
However, not all cities have the capacity to store recycled water in underground aquifers, and for some, the distance from wastewater treatment facilities makes additional recycling costly. The new regulations will allow recycled water to flow directly into local treatment systems, enabling more cities to access potable water even if they lack underground storage.
Sunny Wang, Santa Monica’s Water Resources Manager, noted that the city is constructing one of the most advanced and unique water recycling facilities in the world, capable of harvesting both rainwater and wastewater, all situated beneath the City Hall parking lot. They anticipate implementing direct wastewater recycling as soon as 2027.
The Metropolitan Water District is currently collaborating with the Los Angeles County Department of Public Health to build the largest water recycling system in the world. Currently, approximately 250 million gallons of treated wastewater flow into the ocean each day, failing to meet drinking standards despite being clean. This project aims to reclaim all wastewater to a potable standard.
The regulations surrounding this water recycling initiative are among the strictest in the nation. “People need to psychologically overcome where the water comes from,” Wang explained. Some question why more rainwater isn’t utilized, but in reality, rainwater that drains off streets can carry more contaminants, including heavy metals and oils. “We actually need to use wastewater to dilute rainwater, making it easier to treat,” said Wang, noting that many pollutants in wastewater are organic and thus simpler to manage.
However, implementing such infrastructure comes with a heavy price tag, which may affect water rates. Chaudhuri acknowledged that while the new law could lead to increased water costs, the extent of the increase will vary among water agencies, with the overall construction costs remaining high. The MWD’s water recycling facility is set to reclaim up to 150 million gallons of water daily, at an estimated cost of $6 billion. Meanwhile, Santa Monica’s new plant will cost $96 million, aiming to recycle about 1 million gallons of water each day.
Chaurauri emphasized that recycled water is significantly cheaper than desalinated seawater and that once the infrastructure is in place, the price of recycled water will become comparable to that of imported water. Wang further noted that once the necessary infrastructure is completed, direct potable reuse will likely prove more cost-effective for many cities.
