Is making the Pacific ocean drinkable the best answer to California's drought?

Desalination works for Saudi Arabia. But opponents of the Golden State's plans to follow suit say cutting down on waste is the real key

Some of the 2,000 pressure vessels used to convert seawater into fresh water through reverse osmosis at California’s Carlsbad Desalination Project (AFP)

For Californians struggling to come to terms with a crippling drought, there is something darkly comic about the world’s largest body of water lapping at their shores. Now, with a major desalination project nearing completion in Southern California, some residents of the Golden State will finally start drinking from the Pacific Ocean.

Yet while many experts say desalination is an inevitable component of California’s future strategy for conserving and bolstering its fragile water supply, others insist the process of turning saltwater fresh remains an environmental threat, and that the answer to the state’s water woes is not to find new sources of water, but to better manage those that already exist.

When it begins operating later this year, the $1bn (£650m) Carlsbad Desalination Project is expected to produce approximately 50 million gallons of potable water per day for residents of San Diego County. Planned and approved prior to the drought, it will be the largest such facility in the Western hemisphere, providing around seven per cent of the county’s water supply.

Desalination has been an American dream since at least 1961, when President Kennedy suggested: “If we could ever competitively, at a cheap rate, get fresh water from salt water... it would be in the long-range interests of humanity [and] dwarf any other scientific accomplishments.”

Today there are more than 15,000 desalination plants worldwide, including 2,000 in the US. (Most are small and treat not seawater, but brackish groundwater, a far easier, cheaper process.) Texas and Florida are both reported to be planning new ocean desalination plants, while a handful more are in various stages of development along the California coast.

Desalination can be achieved in one of two ways: thermal treatment, whereby saltwater is boiled and distilled into pure water; or “reverse osmosis”, which forces seawater through a sieve-like membrane that sifts out salt molecules.

The world’s largest thermal desalination plant is the £4.7bn Ras al-Khair facility in Saudi Arabia, which opened last year and is capable of producing approximately 270 million gallons of drinking water per day. This year, the Saudis announced plans to build the world’s first major solar-powered desalination plant, which will treat almost 16 million gallons of seawater per day.

Israel derives some 40 per cent of all its drinking water from desalination. The Carlsbad Project, which will use reverse-osmosis technology, was designed with the help of a leading Israeli firm, IDE Technologies, which built the Sorek desalination plant, which accounts for 20 per cent of Israel’s total supply of potable water.

“Drought is a constant reality in Israel,” said Dr Newsha Ajami, director of urban water policy at Stanford University’s Water in the West programme. “The Israelis use ‘desal’ as part of their water supply portfolio, but they’re also very good at water conservation, re-use and recycling.” If California pursues desalination, Dr Ajami said, it ought to be as part of a similarly diverse portfolio.

Opponents of desalination in California say the more useful case study is Australia, where six vast desalination plants were built in the midst of the last decade’s devastating drought, which then came to an abrupt end with a series of dramatic storms in 2010. Four of the costly plants have been idle almost since their opening.

California experienced a similar, smaller episode during a drought that began in 1987. A $35m (£23m) desalination plant was constructed in Santa Barbara, but after torrential rains in 1993, the facility was mothballed before becoming operational. The city plans to resurrect the plant next year.

Conner Everts, executive director of the Southern California Watershed Alliance and co-chair of the Desal Response Group, which opposes desalination, says Santa Barbara’s and San Diego’s plans are both misguided and premature. “With desal you get a very small amount of very expensive water,” he said. “If people think desal is a sexy, futuristic supply source that will save us from ourselves, and that we’ll be able to keep our exotic lawns and fauna and flora, they’re wrong.”

The desalination industry says major improvements have been made to reverse-osmosis technology, making desalination facilities cheaper to build and to operate, but critics say the plants still guzzle vast amounts of energy, generating carbon dioxide emissions that contribute to climate change. Furthermore, the process itself is damaging to the environment: the intake of seawater and the disposal of waste after its treatment can both be calamitous for local ocean ecosystems.

Debbie Cook, the former mayor of Huntington Beach, where she is fighting a proposal for another major desalination plant, said the technology is totally unnecessary for Southern California. “We have a water management problem, not a water quantity problem,” she said. “We waste so much water. We must completely change our whole outlook: how we allocate water, who owns it, who controls it.”

In fact, with the current drought in its fourth year, Californians are at last beginning to change their behaviour, with cities including Los Angeles planning to provide more potable water from recycling, and people across the state making cuts to their consumption. In the month after Governor Jerry Brown introduced a mandatory 25 per cent reduction in water use across California on 1 April, Californians reportedly used 13.5 per cent less water than in April 2013.

What might sway many against desalination is simply its cost. The Carlsbad Project is expected to drive San Diego water bills up by around $5 per month from an average of $75. In Santa Barbara, residents could pay as much as $20 per month to restore their defunct desalination plant to service. Desalinated water can cost up to twice as much as conventionally treated water.

Then again, said Jay Famiglietti, the senior water scientist at the Nasa Jet Propulsion Laboratory at the California Institute of Technology, that might be a good thing: “Water is always undervalued, and we need to be paying for the stuff. Even if the price goes up, it’s probably still going to be way less expensive than the true cost of water.”