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Recycled Water May Prove Crucial for Northern California Amid Ongoing Droughts, Climate Change

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our beakers with water and pipes in the background.
Beakers on display show results of the four steps in the water-purification process: treated wastewater, microfiltration, reverse osmosis and purified water, at the Silicon Valley Advanced Water Purification Center in San José on Sept. 23, 2021. (Beth LaBerge/KQED)

The San Francisco Bay Area is far behind Southern California in reusing water. Policy experts say it could take decades for the state’s second-most populous region to catch up — the lower half of the state recycled 83% more water than the Bay Area last year.

Standing outside Google’s Bay View campus in Mountain View in early August, wearing a pool-blue collared shirt and a gray blazer, California's Natural Resources Secretary Wade Crowfoot pressed the state's northern region to do more.

“If you spend time in Orange County, there's a chance that you're consuming purified water that's been recycled,” he said. “We need to expand water recycling throughout the Bay Area.”

With two multiyear droughts in a decade and the pace of human-caused climate change accelerating each year due to the burning of fossil fuels, agencies across the region are finally grappling with the need for more recycled water and whether to expand the purple pipe systems that carry it. Boosting water recycling around the Bay Area could have a secondary benefit: preventing red tides or algal blooms in the bay that threaten marine life.

“Southern California communities, they've kind of had to grapple with this, crack this nut and solve this problem a little bit sooner than other California communities,” said Annalisa Kihara, assistant deputy director of the division of water quality with the State Water Resources Control Board.

Scientists project that California’s climate will grow more arid and could provide 10% less water statewide by 2040. Kihara said recycled water must be part of the state’s plan to adapt to drought.

But most water agencies in the nine Bay Area counties are cautiously waiting to invest until the long-awaited, state-approved regulations for mixing toilet water and tap water — what officials call "direct potable reuse" — go into effect.

Recycled wastewater is currently not allowed to be directly pumped into drinking water sources, but the new rules, which could go into effect in late 2023, might change that, ushering in a new era of water treatment in California.

Gov. Gavin Newsom has called for the state to increase water recycling by 60% by 2040, or 1.8 million acre-feet yearly. Last year, the state recycled 731,000 acre-feet and will need to spend billions of dollars to reach that 2040 target.

The Bay Area hasn’t truly taken the leap into large-scale water recycling, with a few exceptions. In 2021, from Healdsburg to San José, the region recycled nearly 78,000 acre-feet of water, a small fraction of what the region uses yearly.

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Historical necessity is part of the reason that Southern California is so far ahead of the Bay Area. Most of the rain falls in the northern part of the state, and yet most Californians live in the southern part of the state (the Bay Area’s population of 8 million is about a third of that of Southern California).

But Felicia Marcus, visiting fellow at Stanford University’s Water in the West program and past chair of the California State Water Resources Control Board, notes that San Francisco, Santa Clara and other Bay Area counties also rely on water from other places.

“Many in the Bay Area don't realize that they are just as dependent on imported water as Southern California (is). The majority of our water comes from 100 miles away,” she said.

Southern California invested in water recycling first because they have fewer rights to water from the Sierra Nevada. But now that the Bay Area faces increasingly hot summers and droughts super-fueled by climate change, Marcus said the region must follow.

A solution for red tides?

Earlier this year, the worst ecological disaster in recent memory gripped the Bay Area. An algal bloom killed thousands of fish across the Bay Area. Scores of bat ray, crab, flounder and striped bass carcasses washed up along the shoreline from Lake Merritt to Fort Funston to Oyster Point in San Mateo County.

Scientists aren’t entirely sure what caused the algal bloom but believe the red tide, vividly seen from the sky, is climate-related and linked to treated sewage.

“We just experienced this horrendous algae bloom and fish-kill,” Marcus said. “A lot of that has to do with nutrients in the waterway.”

A large, outdoor, metal, circular water purification tank, maybe four stories high and half a block in diamteter.
Water remains in a finishing tank until blending at the Silicon Valley Advanced Water Purification Center in San José on Sept. 23, 2021. (Beth LaBerge/KQED)

Wastewater treatment plants unload nutrients — cleaned-up particles of human waste — as a by-product released into the bay. Marcus said that if the Bay Area cleans wastewater to a higher level and reuses much of that water rather than dumping it, it could prevent harmful algal blooms in the bay.

The San Francisco Bay Regional Water Quality Control Board, which regulates wastewater treatment across the region, is mandating that all agencies study the impact water recycling could have on their operations and the bay.

“We're feeling pretty confident that the nutrients in the bay help the bloom grow,” said Eileen White, head of the agency. “It’s one of the reasons we're asking wastewater utilities to look at recycled water.”

White said the final results could come next summer. The price to update wastewater treatment plants to better account for nutrient loading could cost in the ballpark of $12 billion, according to the Bay Area Clean Water Agencies, which represents the plants.

'It's the perfect time'

Valley Water, which serves more than 2 million residents in the South Bay, is one of the agencies eagerly awaiting the state’s decision on direct potable reuse. The agency runs a wastewater recycling plant and by 2025 aims to double the 5% of the water it recycles yearly.

That’s enough to supply 74,000 households with water a year. But Marcus says that’s chump change compared to what is needed.

“I don't understand why Valley Water is only going for 10% when they are perhaps the most vulnerable population of a large city,” she said. “You would think they would put the pedal to the metal on everything.”

One of the reasons Valley Water isn’t doing more is because of the cost — millions, if not billions, of dollars in both upfront and long-term maintenance, which could significantly decrease with state and federal infrastructure dollars.

It’s pricey to build a water recycling facility, but even more costly to create a separate system to transport water, said Kirsten Struve, the agency’s assistant officer for water supply.

The ultraviolet-light step in the water purification process at Silicon Valley Advanced Water Purification Center in San José on Sept. 23, 2021. (Beth LaBerge/KQED)

“Once direct potable is an option, recycled water can go to one of our drinking-water treatment plants and we wouldn't need a whole new pipe system,” she said.

Up the peninsula, the San Francisco-Peninsula Regional PureWater Project is leading an effort to turn 12 million gallons of wastewater daily into drinking water. They’d like to store the recycled water in a reservoir or pump it straight into drinking water pipes.

“The concept that we take potable drinking water, poo and pee in it, and just flush it down the toilet is a travesty,” said Teresa Herrera, Silicon Valley Clean Water manager. Herrera is leading the project to help secure drinking water supplies between Redwood City and San Francisco.

The project is in its early phases. Herrera said a proposal outlining the next steps could come next year.

The real leader of water recycling in the Bay Area is Santa Rosa, which reuses 98% of its wastewater. The agency pipes recycled water to three other cities — Rohnert Park, Cotati and Sebastopol, as well as additional, unincorporated areas — a geothermal energy operation, and farms, said Jennifer Burke, director of Santa Rosa Water.

This past summer, Santa Rosa began a study on how to make the city’s water system climate-resilient. It includes a focus group considering adding direct potable reuse to its existing water recycling system.

“This allows us to prepare for the future,” Burke said.

'I don't think we should feel numb'

As Bay Area water agencies begin boosting water recycling, Charisma Acey, city and regional planning professor at UC Berkeley, worries that affluent neighborhoods might receive tasty mountain-sourced Hetch Hetchy water and lower-income communities of color will be delivered recycled wastewater.

“We need to make sure things don't become tiered where one level of service that's perceived as inferior, even though it might be far more environmentally friendly, is only used by one group of society,” she said.

On another point about equity, Samuel Sandoval Solís, professor of water resources management at UC Davis, said if the Bay Area recycles enough water, decreasing demand on the Sierra, some of that water saved could be made available for the more than 1 million people in the state — mainly in the Central Valley — who don’t have access to clean and affordable drinking water.

“The conversation should focus on how we can provide water to these million people that, by the way, put a lot of food on the table for people in the Bay Area,” he said. “I don't think we should feel numb by this number.”



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