To state the obvious: California has a water problem. That’s why more than 6 million Southern Californians can water outside only once or twice a week as of June 1.
But experts say conservation alone can’t solve our water woes. So what does water security look like in a drier future? This story focuses on one piece of the puzzle: recycling wastewater. Let’s dig in.
Turning Black And Gray Into Crystal-Clear
I’m standing in front of a steel sink at the headquarters of the Orange County Water District, holding a cup of water.
“This water,” said Mehul Patel, the operations director, “probably about 30 hours ago was raw sewage coming through the sewer collection system.”
So why the heck am I about to drink it?
Most of the water we use in cities in the Southland is piped hundreds of miles from reservoirs in Northern California and the Colorado River. In good years, those reservoirs are filled by snowmelt and rain. But after the driest winter ever recorded, they’re at historically low levels.
If society doesn’t dramatically reduce emissions and slow the climate emergency within this decade, as much as 65% of the snowmelt that feeds those northern reservoirs could be lost by the end of the century. And the Colorado River is being stretched thin by an ongoing “megadrought” — the worst in 1,200 years, made even worse by humanity’s pumping of greenhouse gases into the atmosphere.
“Our main water supply right now, which is imported, is only going down,” said Dan McCurry, an engineering professor at USC.
It’s clear our main sources of water are in peril. That’s why millions of Southern Californians are under strict new drought rules. But experts say conservation alone can’t solve our water woes — we need to reuse more water … even for drinking.
We’ll need to more efficiently conserve water at homes and businesses. Incentivizing water-efficient technologies and conservation practices could reduce urban water use in California by as much as 48%.
We need to recycle more wastewater. Nearly 75% of treated wastewater in California is currently dumped in the ocean. That water could be used for irrigation and industrial purposes or further purified for drinking.
We need to capture and store more stormwater as wet weather becomes less frequent and predictable.
The study doesn't address this, but ocean desalination is expected to play a role in the near future. However, researchers and environmentalists largely agree it should be a last resort given how costly and energy-intensive the process is. It can also be damaging to marine life. You can read more on two southern California desalination plants here.
The Need For Local Water Supplies
In L.A., all of the water that goes to houses, apartments, and businesses is potable (drinkable, in other words), including the water used to irrigate lawns and plants outside, according to the L.A. Department of Water and Power (LADWP).
That’s because it all has to go through the same pipe system. And nearly all of that water is imported from up north, the eastern Sierra and the Colorado River.
So it can feel jarring to drive around town and see sprinklers feeding lush parks, golf courses and even street medians when you’re being asked to drastically cut your own water use. But many of these areas are exempt from the watering restrictions because they use non-potable, recycled wastewater to irrigate, according to LADWP. That water is distributed through a separate pipe system built just for that purpose.
Wastewater is all the water that goes down our drains or is flushed down our toilets. In other words, it’s a more palatable way of saying “sewage.”
Only about 2% of L.A.’s water is recycled. Across the state, about 24% of cities’ water is recycled, according to the Pacific Institute. Most of that recycled water irrigates places such as farms, parks, and golf courses. Less than a third of it is treated to be drinkable, according to the State Water Resources Control Board.
But as extreme drought becomes increasingly common and traditional water supplies dwindle, cities will need to recycle more of that water for drinking, McCurry said. That’s the focus of his research.
“Recycled wastewater is the most secure option we have in the long term for ensuring a steady water supply,” he said.
How Wastewater Recycling Works
The world’s largest facility that recycles wastewater for drinking isn’t in Saudi Arabia or Israel — it’s in Fountain Valley. It’s called the Groundwater Replenishment System (GWRS), and it’s where much of Orange County’s wastewater ends up.
The waste is treated first at a nearby sanitation plant, where most of the solids are removed. Then it flows through pipes to the GWRS, where it’s put through three main treatments to be purified for drinking, said Patel, the operations director. He showed me around the facility.
The first step is called microfiltration, which removes any remaining solids from the water.
It’s basically like a super advanced coffee filter: the water is run through a material with microscopic pores that are about 1/300th the diameter of a human hair, Patel explained.
This is the level of treatment most recycled water gets — after this step, the water could be used to irrigate parks or golf courses, Patel said. Or it could be dumped in the ocean, which is where most of L.A.’s treated wastewater currently ends up.
We pause in a large warehouse with rows upon rows of cylindrical contraptions stacked on top of each other. The place vibrates with a loud hum.
“This is the heart of the treatment … this is the reverse osmosis,” Patel said.
Reverse osmosis is an even more advanced version of microfiltration. The water is once again squeezed through a membrane to filter out microscopic contaminants.
“This will remove all the emerging contaminants, things that people worry about: the salts, the organics,” Patel said. “This gets the water to a level where it's almost distilled quality.”
The water is so pure, they actually have to add minerals back in, Patel said.
In the third step, the water is blasted with high amounts of ultraviolet light and hydrogen peroxide in a process called UV advanced oxidation. The water is tested at each step, Patel said.
Finally, before it’s distributed to homes and businesses, the water is injected into a huge groundwater basin that spans the north and central parts of Orange County where it mixes with other drinking water sources and eventually spills once again from O.C. faucets.
All hope’s not lost by any means. And taking advantage of technology and science — we can solve a lot of problems.
GWRS recycles about 100 million gallons of drinkable water per day —and the water district is expanding the plant to make 130 million gallons per day. That’s enough drinking water for more than a million people.
This facility is essential in the face of a drier future, Patel said.
“All hope’s not lost by any means,” he said. “And taking advantage of technology and science — we can solve a lot of problems.”
But politics — and the public’s own queasiness — has slowed progress to expand wastewater recycling in cities across the state.
So Why Aren’t We Drinking More Recycled Water?
The idea of recycling wastewater for drinking is nothing new. More than 20 years ago, the concept was gaining momentum. But politicians, business interests, and some media sensationalism got in the way.
The infamous phrase “toilet-to-tap” was born. Some newspaper editors used the catchy phrase in headlines and articles across the Southland —and the country. Late-night talk show hosts used it as a punchline. Politicians used it as a talking point.
“Go tell somebody in North Hollywood that they have to drink toilet water, but the mayor [Richard Riordan] won’t have to drink it in Brentwood,” former L.A. Mayor candidate Joel Wachs reportedly said. He was one of the most vocal opponents of the idea.
The political rhetoric and sensationalism around the topic sparked massive public resistance. As a result, earlier wastewater recycling projects ended up shelved.
But worsening drought cycles, improved technology, and more widespread recognition of the severity of the climate crisis is eroding public and political resistance.
California law currently doesn’t allow cities to put recycled wastewater directly into municipal water distribution systems. Instead, cities are required to first inject that water underground into an aquifer, where further, natural filtration occurs.
This is called indirect potable reuse and it’s a big reason why the Orange County Water District was able to build its wastewater recycling plant —it sits on top of one of the largest groundwater basins in coastal California. But other cities aren’t so lucky.
“It’s just purely an accident of geology whether your city happens to be situated over something like a groundwater aquifer or not,” said McCurry. “If that's the case, then you're shut out from potable reuse right now in California.”
But the state is working on regulations for what’s called direct potable reuse. That would allow cities to pump treated wastewater directly into an above-ground reservoir, instead of underground first, McCurry said.
“It's just a much more accessible way to be able to reuse because it doesn't require that you won the geological lottery,” McCurry said.
It can also make the process cheaper, more efficient and less energy intensive because it takes out a step in the current process, he explained.
Lawmakers are expected to finalize regulations for direct potable reuse by 2023. That’ll be important for L.A.’s own wastewater recycling plans: the city is expanding the Hyperion treatment plant near Santa Monica Bay to recycle enough wastewater to provide 40% of Angelenos’ drinking water needs by 2035.
But the westside of L.A. has limited underground aquifers, said Traci Minamide, the chief operating officer of L.A. Sanitation and Environment (LASAN), the agency overseeing the project along with LADWP.
“We've got more water than there is space,” Minamide said.
The wastewater L.A. currently recycles isn’t treated to be drinkable. It’s siphoned through an entirely different system, called "purple pipes." Starting in the 1980s, the city built these pipes to get big water users such as refineries, golf courses, hospitals and others to cut down on their use of drinkable water. Only 70 customers, both government-owned and private, receive this non-potable water, according to LADWP.
In the meantime, every day about 225 million gallons of treated wastewater is dumped into the Santa Monica Bay. With the help of these new regulations, the city expects to recycle all of that to drinkable standards.
“It’s a major game-changer,” said Jesus Gonzalez, LADWP’s water recycling policy manager.
The project is estimated to cost $16 billion and will require massive updates to pipe infrastructure throughout the city, but Gonzalez said that’s a drop in the bucket when it comes to securing water supplies for future generations. Though the up-front cost may be significant, today, depending on local infrastructure, recycled water can be cheaper than imported — Orange County’s recycling plant provides an example.
Imported water currently costs about $1,143 per acre-foot, while GWRS water costs $704 per acre-foot, said Gina Ayala, the water district’s public affairs director. That translates to about $28 in monthly savings for Orange County residents who get their water from GWRS, she said.
L.A. is working on its own mini version of GWRS to be up and running by 2027 — it’ll provide enough water for about 200,000 people, according to LADWP. The Metropolitan Water District of Southern California, which just enacted all those outdoor watering restrictions, is working on a region-wide wastewater recycling project as well.
There’s broad consensus that recycling more wastewater is the way of the future. Environmental group L.A. Waterkeeper even sued the state (and won) to get L.A. to recycle more of its wastewater. And non-profit group Los Angeles Alliance for a New Economy wants the state to invest more in wastewater recycling projects because it says it will benefit low-income ratepayers overburdened by rising utility costs, and be a source of union jobs, said Lauren Ahkiam, the organization’s Water Justice Campaign director.
Back at Orange County’s recycling plant, I’m standing in front of three metal sinks that display wastewater at different stages of treatment.
One sink holds lightly-tinted water — what it looks like after all solids have been removed. Then there’s a sink with gross, dark brown water —that’s everything that’s filtered out next, during reverse osmosis.
The third sink holds clear water — the water that’s gone through all three treatment stages. I fill up my cup.
“Don't be biased by its origin,” Patel said. “Think of it where it is now.”
I take a sip — and it sure tastes good.