February 29, 2024

When flushing a toilet Californiathe water can end up in many places: an ice rink in Ontario, ski slopes around Lake Tahoe, farmland in the central valley.

And – soon – kitchen taps.

California regulators on Tuesday approved rules to allow water agencies to recycle wastewater and pour it into the pipes that carry drinking water to homes, schools and businesses.

It’s a major step for a state that has struggled for decades to secure reliable sources of drinking water for its more than 39 million residents, and it signals a shift in public opinion on a subject that as recently as two decades ago caused a similar backlash. projects.

Since then, California has been through several extreme droughts, including the most recent one, which scientists say was the driest three-year period on record and left the state’s reservoirs at dangerously low levels.

“Water is so precious in California. It’s important that we use it more than once,” says Jennifer West, the managing director of WateReuse California, a group that advocates for recycled water.

California has been using recycled wastewater for decades. The Ontario Reign minor league hockey team used it to make ice for its rink in southern California. Soda Springs Ski Resort near Lake Tahoe used it to make snow. And farmers in the central valley, where many of the country’s vegetables, fruits and nuts are grown, use it to irrigate their crops.

It was not used directly for drinking water. Orange County in southern California operates a large water treatment system that recycles wastewater and uses it to recharge underground aquifers. The water mixes with the groundwater for months before it is pumped up again and used for drinking water.

California’s new rules will allow water agencies to take wastewater, treat it and put it into the drinking water system (although it is not required). California would be only the second state to allow it, after Colorado.

It took regulators more than 10 years to develop these rules, a process that included multiple reviews by independent panels of scientists. A state law required the California Water Resources Control Board to approve these regulations by Dec. 31 — a deadline just days away.

The vote was heralded by some of the state’s largest water agencies, all of which have plans to build large water recycling plants in the coming years. The metropolitan water district of southern California, which serves 19 million people, aims to produce up to 150m liters (nearly 570m liters) per day of both direct and indirect recycled water. A project in San Diego aims to supply nearly half of the city’s water by 2035.

Water agencies will need public support to complete these projects – which means convincing customers that recycled water is not only safe to drink, but it’s not difficult.

California’s new rules require that the wastewater be treated for all pathogens and viruses, even if the pathogens and viruses are not in the wastewater. That’s different from regular water treatment rules, which require treatment only for known pathogens, said Darrin Polhemus, the deputy director of the drinking water division for the California Water Resources Control Board.

In fact, the treatment is so rigorous that it removes all the minerals that make fresh drinking water taste good – meaning they have to be added back at the end of the process.

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“It has the same drinking water quality, and probably better in many cases,” Polhemus said.

Building these treatment facilities is expensive and time-consuming, so, Polhemus said, they will only be an option for larger, well-funded cities – at least initially.

In San José, local officials opened the Silicon Valley Advanced Water Purification Center for public tours “so people can see that it’s a very high-tech process that makes sure the water is super clean,” said Kirsten Struve, the assistant officer for the water supply department at the Santa Clara Valley Water District.

Right now, the agency uses the water for things like irrigating parks and playgrounds. But they plan to use it for drinking water in the future.

“We live in California, where the drought occurs all the time. And with climate change it will only get worse,” Struve said. “And it is a drought-resistant supply that we will need in the future to meet the demands of our communities.”

Joaquin Esquivel, the chairman of the state Water Resources Control Board, which approved the new rules Tuesday, noted that most people already drink recycled water: Most wastewater treatment plants put their treated water back into rivers and streams, which then flow down to the next town so they it can drink.

“Anybody out there who discharges drinking water downstream from a wastewater treatment plant — which, I promise you, you all do — is already drinking toilet-to-faucet,” Esquivel said. “All water is recycled. What we have here are standards, science and – importantly – monitoring that allows us to believe that it is pure water.”


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