Can This Solar Desalination Startup Solve California Water Woes?

As drought plagues California, the nation’s largest agricultural producer, could this startup make it easier for farmers in the Central Valley to mine a local, undrinkable water supply?

Despite a few recent drops of rain in some parts of the state, California is still in the middle of what might be the worst drought in half a millennium. That’s bad news not only for residents, but also for anyone who likes to eat, since California supplies the country with more food, by far, than any other state. And the vast majority of the water that falls in California goes not to showers or swimming pools, but to agriculture.


While there are several ways to conserve water– like drip irrigation– one of the most interesting potential solutions to California’s water woes is desalination. A startup called WaterFX is pioneering one new ultra-efficient, solar-powered method that could help the technology become more cost-effective and sustainable.

Since WaterFX uses renewable energy, and regular desalination uses massive amounts of electricity, the solar tech can help push costs down for producing freshwater. It could also make it possible for farmers in the Central Valley– the most productive farming region in the world– to use local water instead of relying on aqueducts pumping water from hundreds of miles away.

That’s because the Central Valley happens to have a lot of salty water that can’t otherwise be used. The area is naturally salty, and every time a farmer irrigates a field, he also end up pumping salty water out of the soil. Farmers have been struggling to find a economical way to dispose of the runoff, which can harm wildlife and the ecosystem.

“What we’re trying to show is that treating the water doesn’t have to be a cost, it can actually be a new source of water,” says Aaron Mandell, the founder of WaterFX. Through the technology, runoff can be treated and used again in a loop. Salty groundwater in the region can also be treated to become freshwater. In areas near the ocean, seawater can also be treated.

Ultimately, Mandell believes the technology can help California become more water independent, and even potentially become an exporter of water.

“There are other examples around the world where a concerted effort and investment in desalination technology has actually led to a surplus of water,” he explains. “If you look at Israel, they’re actually exporting water now. And Israel is just as water scarce, if not more, than California.”


Since solar desalination can enable the use of local water, it can also help reduce one of the state’s biggest uses of energy–pumping water through the aqueduct system.

Besides saving electricity, the technology has other advantages. Regular desalination, which uses high pressure system, can only create a limited amount of freshwater; half of the original saltwater ends up unusable, so salty that when it’s dumped back in the ocean it can harm marine life. WaterFX, on the other hand, claims its process has a 93% water recovery rate. The remaining salt is so concentrated that it can actually be turned into something useful, like gypsum, a salt used in making drywall, or epsom salts.

Mandell hopes to spread the technology quickly by making some of it open source and by adopting a business model that leases its equipment to customers. “We intend to give people the basic building blocks for how you can replicate this in other places, and encourage entrepreneurs to basically follow our lead,” he says.

For now, the company is working on a pilot project with the Panoche Water District in the Central Valley, and focusing on bringing it up to commercial scale. They hope to be producing 2 million gallons by the end of 2014. That won’t solve California’s current drought crisis, but hopefully it is a sign of good things to come.

About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.