California approves rules for recycling toilet water for drinking purposes

Regulators said they hope the measure can help build a climate-resilient water source for the drought-prone state

California regulators have unanimously voted in favour of allowing water agencies to recycle sewage water for drinking purposes.

On Tuesday, the state’s Water Resources Control Board laid out the steps for how recycled wastewater will be treated before it is pumped into Californians’ kitchen faucets. The board said in a press release that the decision to combat water scarcity would make California more resilient to hotter and drier conditions.

The process used to recycle the water is known as direct potable reuse and can produce results in a matter of hours. The many steps in the long process were outlined in detail in a 63-page document.

A report on the measure was initially submitted by a panel of 12 scientists and engineers in 2016, and the following year the board was tasked with establishing water recycling criteria for the implementation of the measure that was also protective of public health.

The vote on Tuesday comes months after the state required that the board approve the criteria before 31 December. The regulations are now headed to the Office of Administrative Law, which is expected to give final approval sometime next year, Cal Matters reports.

According to the board, the system is among “the most advanced standards in the nation for treating wastewater to such an extent that the finished product meets or exceeds current drinking water standards.”

For decades now, California has struggled to secure water supply for its more than 39 million residents. Record droughts in recent years have exacerbated that issue.

The new regulations signal a shift in public opinion on a subject that as recently as two decades ago prompted backlash.

Lakeisha Bryant, public information representative at the Santa Clara Valley Water District, holds flasks of water before and after it is purified at the Silicon Valley Advance Purification Center, Wednesday, Dec. 13, 2023, in San Jose, Calif (AP)

That’s different from regular water treatment rules, which only require treatment for known pathogens. The treatment is so stringent it removes all of the minerals that make fresh drinking water taste good — meaning they have to be added back at the end of the process.

Regulators said they hope the measure can help build a climate-resilient water source and reduce the sewage water released to bodies of water.

The vote does not require all water agencies to implement the system, but the agencies that do must treat the water for potential pathogens and viruses.

The Silicon Valley Advance Water Purification Center is pictured Wednesday, Dec. 13, 2023 (AP)

The San Jose-Santa Clara Regional wastewater facility is seen, Wednesday, Dec. 13, 2023, in San Jose, Calif. Sewage water is treated at the site before it is discharged into San Francisco Bay (AP)

In San Jose, local officials have opened the Silicon Valley Advanced Water Purification Center for public tours “so that people can see that this is a very high-tech process that ensures the water is super clean,” Kirsten Struve, assistant officer for the water supply division at the Santa Clara Valley Water District, told The Associated Press.

“The newly adopted regulations comply with California’s Safe Drinking Water Act, which ensures that the water delivered by public water systems in California shall at all times be pure, wholesome, and safe to drink,” the board said.

Plans to implement direct potable reuse were first made public during the summer. The board said that it had gathered feedback from the public and adjusted the initial criteria based on that commentary.

“This is an exciting development in the state’s ongoing efforts to find innovative solutions to the challenges of extreme weather driven by climate change,” Joaquin Esquivel, chair of the State Water Board, said in a statement. “On top of helping us build drought-resilient water supplies, direct potable reuse offers energy savings and environmental benefits. And most importantly, these regulations ensure that the water produced is not only safe, but purer than many drinking water sources we now rely on.”