The constant search for drinkable water in arid Southern California soon could tap into a new resource – the brackish ocean water that seeps into the southwestern edge of Orange County’s huge natural aquifer.
A small coalition that includes two local water agencies (Mesa Water and the Orange County Water District) and two Orange County cities (Newport Beach and Huntington Beach) said on Monday, June 24 that they’d received $250,000 in federal money to look at the possibility of turning brackish water – water that’s got too much salt to be potable but not as much salt as what you’d find in the open ocean – into stuff people can drink.
The idea isn’t new. People in Torrance and parts of Riverside and San Bernardino counties already drink brackish water, after it’s been treated in a pressurized filtration process similar to the technology used when turning ocean water into tap water.
Still, the concept hasn’t been common in Orange County, even though water officials have known for decades that brackish water flows into the local aquifer, particularly in areas near the coast in Huntington Beach and Upper Newport Bay.
How much of that might be ripe for transformation – and the cost of doing so – are two questions that figure to be answered by next spring.
“We have a lot of people and not a lot of water. So, we’re constantly looking for the next source of water,” said Paul Shoenberger, general manager for Mesa Water, which is the lead agency on the study.
“But each new source is a little more expensive than the last,” he added.
The county – and, specifically, Mesa Water – have been leaders in finding new and sometimes non-traditional sources for water.
Much of the water used by about 2.5 million people who live in north and central Orange County is stored in a natural underground aquifer that runs from just beneath the county’s north and central coasts to underground Yorba Linda, reaching a depth of more than 2,000 feet at some points. The aquifer, in turn, is supplied by the Santa Ana River and rainwater reclamation, which includes a series of storage pools that flow and ebb during the winter storm season.
But some of the other sources that supply Orange County with drinkable water are expected to become less secure in coming years.
For example, the water imported into Orange County from the Colorado River and northern California – water that’s mostly used by about 800,000 people who live in communities in south Orange County – is expected to become more expensive as the climate changes and as federal regulations limit that supply.
Another source – one that’s been pioneered by Mesa Water – isn’t expected to ever be a key factor outside of that district.
Mesa, which provides water to about 110,000 people in Costa Mesa and parts of Newport Beach and unincorporated county neighborhoods near John Wayne Airport, has drilled below the county’s aquifer to find something known as “amber” water since the early 2000s. The amber water is tapped from an area that developed about 100,000 years ago, with its coloring coming from remnants of long-dead redwood forests and ferns that once were common to this region. To date, Mesa and Irvine Ranch Water District are the only agencies tapping amber water, and it’s unclear how big a resource it would be if more agencies tried to do the same.
Another water source also is close to tapping out.
Orange County, for decades, has been a national leader in water recycling. The process once viewed whimsically as “toilet to tap” is now a widely accepted (and increasingly copied) technology, using massive filtration systems to harvest water used in everything from household taps to showers to dishwashers and reusing it for those same purposes.
Though that process has been used locally for many years, and now produces about 130 million gallons of water every day – roughly the same as what the county gets out of the Santa Ana River – Shoenberger noted that local water recycling reached maximum capacity only in the past year or so.
That means any net gains in local water supply will have to come from other sources.
“We no longer have the option of expanding our recycled water,” he said. “So, now, we’re at the point where everything locally has been tapped.”
Another factor prompting the exploration of brackish water is the California Coastal Commission’s decision, in 2022, to reject a $2.5 billion desalination project off the coast of Huntington Beach.
That project, from Poseidon Water, was pitched as a way to end the county’s need for imported water. But questions about cost and the harm the proposed desalination technology would do to the ocean prompted local organizations and many environmental groups to fight – and eventually defeat – the Poseidon project.
Using brackish water probably wouldn’t get the same pushback.
The water seeps into the aquifer naturally, so getting to it probably won’t require any construction or energy-intensive pumping. Also, brackish water already is segregated within the aquifer through a series of liquid barriers known as “injection wells.”
What’s more, its primary contaminant – salt – is already removed from at least some of the county’s drinking water supply. The process of doing that is based on pressurization; essentially squeezing the salt out of the water.
So, when it comes to the brackish water, the basic question comes down to how much salt it has. Removing a lot of it would require a lot of pressure and, as a result of that, a lot of energy. Less salt would mean less of everything else.
“It’s probably more energy intensive than pumping out groundwater,” said Andrew Wiesner, an engineer for Mesa Water. “But compared with seawater, it’s significantly less energy intensive.”
Salinity is one of dozens of questions to be determined during the study – known as the local groundwater Supply Improvement Project (Local SIP) — which now is slated to begin in August.
Mesa officials said the technical side of the idea will be looked at by geologists and water experts and engineers. Other experts will look at long-term cost projections and the area’s potential need for water.
When the first phase of Local SIP is finished, probably in April of next year, Shoenberger said the group will have three options.
“We could do nothing. We could choose to (extend) the study. Or we could go whole hog and get started.”
Issues such as cost, long-term financing and pricing are not yet known, Shoenberger said.
Future need also isn’t clear. The county’s population currently is a bit over 3.2 million. By 2050, according to a projection from the Orange County Water District, the county’s population will grow to about 3.3 million.
The Irvine Ranch Water District uses amber water, joining Mesa Water as Orange County water districts using that resource. Because of a reporting error, the number of districts tapping into amber water was incorrect in an earlier version of this story. This version has been updated.
