A historic drought is crippling California. A third of the nation’s fruit, vegetables, and nuts come from the state’s Central Valley, so it’s a problem that affects us all. Governor Jerry Brown has ordered cities and towns to cut water usage by 25 percent. And officials say it’s more important than ever to recycle water—even the water used to flush the toilet.
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Would You Drink This Water?
Recycled sewage water is helping California survive one of the worst droughts in its history
BONE DRY
Last year was the warmest and the third driest recorded in California in the past 119 years, according to Laurel Rogers of the U.S. Geological Survey’s California Water Science Center.
The Arangio family recently moved to Santa Clara County in Northern California, and they see signs of drought all around them. “Rivers are dry,” says Lily Arangio, 10.
“Some people think it’s awful if you water your lawn,” says her sister Caroline, 12.
The state has received only two thirds of the usual amount of precipitation over the past three years. And this year scientists discovered that the spring snowpack in the Sierra Nevada Mountains was down to just 5 percent of the normal amount. Snowpack consists of layers of snow that accumulate in high, cold places during the winter. As California’s snowpack slowly melts during the spring, it becomes an important source of water for the entire state.
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“During the drought, people are relying much more heavily on groundwater,” says Rogers. Groundwater is water that collects below Earth’s surface. About 40 percent of California’s drinking-water supply comes from groundwater. In the Central Valley, where pumping from underground sources isn’t regulated, farmers have drawn so heavily on groundwater that the entire valley has started to sink. This subsidence happens when aquifers—layers of rock that absorb and hold water—are emptied out and start to compress. The sinking of the land can damage roads, bridges, and buildings.
In the more populous southern part of the state, engineers have developed a way to recapture the water flushed down hundreds of thousands of toilets in Orange County, near Los Angeles. They purify it and send it back to the drinking-water supply.
“We were looking for a drought-resistant supply of water,” says Mehul Patel, the program manager for the Orange County Groundwater Replenishment System—the facility responsible for making the water from toilets clean enough to drink.
TOILET TO TAP
How does the county’s water go from toilet to tap? First the sewage department captures wastewater from toilets, sinks, and showers. It runs the water through a standard sewage treatment plant, where it comes out clean enough to be dumped into the Pacific Ocean.
But rather than put the treated water out to sea, workers send it through an elaborate system of pipes, filters, and tanks, where it undergoes a purification process. Sophisticated filters trap large contaminants (like most bacteria) and remove salt, prescription drugs, and other unwanted chemicals that may be lurking in the water. Then ultraviolet light and hydrogen peroxide kill any remaining bacteria, viruses, or other living contaminants.
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The purified water is carefully checked for safety. The treated water is actually so pure that minerals have to be added in for flavor, because without them it’s too bland.
After the steps are completed, about 40 percent of the purified water is injected into the ground near the coast. That stops water levels from dropping too low in the groundwater basin there. If those water levels were allowed to fall too far, salty Pacific Ocean water could flow in and ruin the supply of fresh water that many people rely on.
The rest of the purified water is pumped into lakes. The water slowly seeps down through layers of clay and rock and eventually ends up in the groundwater, helping to replenish the drinking-water supply.
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A SCARY FIRST SIP
There’s no denying it: The idea of downing water that started out in your toilet takes some getting used to.
Getting the first “toilet to tap” plant built in Orange County back in 2008 was difficult. Another California city, San Diego, blocked construction of a similar plant because people were disgusted by the idea of drinking water that once contained poop.
But since 2008, California’s drought has gotten more severe. And many people in Orange County have safely consumed the purified wastewater for the past seven years. Patel says those factors are helping area residents get onboard with water recycling.
The water recycling plant in Orange County recently expanded from 70 million gallons a day to 100 million gallons. The once-protested plant in San Diego is back on track and could be recycling 30 million gallons of water a day by 2021. New water recycling plants are also being constructed in Arizona and Texas.
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A wastewater recycling plant has been proposed near the Arangio family’s new home, so they may get a chance to drink recycled water in the future. Like many California residents, Lily Arangio thinks the idea of toilet to tap is “gross” but also brilliant. “I’d be brave enough to give it a try,” Lily says.
After California’s successful water recycling efforts, other states are facing less of the dreaded “yuck factor.” In the Texas cities of Wichita Falls and Big Spring, facilities even send water from the recycling plant to a water treatment plant and then directly into the water supply—skipping the trip through the underground aquifers.
Patel thinks that’s a natural next step for California, too. The only reason recycled water in California is pumped into the aquifer is that state law requires it, not because the trip makes the water any cleaner or safer, Patel says. “Pipe to pipe may need to be a reality in the future,” he says.
CORE QUESTION: What steps are involved in purifying wastewater to make it clean and safe to drink?
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