The California Coastal Commission last week green-lit a $140 million desalination plant in south Orange County’s Dana Point, a pivot from its unanimous rejection in May of another controversial desalination project in the county.

The decision indicates that state regulators see a place for new seawater desalination plants in California to bolster water supplies, particularly for coastal areas with few water sources of their own.

“We believe that the project before you today, although not perfect, provides a solid example that we can use in planning for future desalination,” Kate Huckelbridge, a senior deputy director, told the Coastal Commission.

The South Coast Water District’s Doheny Ocean Desalination project, which the commission unanimously approved, would help serve the district’s roughly 35,000 residents in Dana Point, South Laguna Beach and parts of San Clemente and San Juan Capistrano.

Wells running from Doheny State Beach would pull water from beneath the ocean floor, which would then be piped to the desalination facility inland of the Pacific Coast Highway in Dana Point.

The Coastal Commission cited the project’s efforts to avoid harming marine life, as well as the need to buffer local water supplies. These communities rely almost entirely on water imported from Northern California and the Colorado River, rendering them vulnerable to drought and earthquakes that could damage critical water lines.

“I feel that the commission has been under kind of a cloud of doubt from the people who believe in desal — that we were somehow going to turn down any project whether it was a good one or a bad one,” said commissioner Dayna Bochco. “And I’m glad now that we can show the other agencies and whoever else is interested in this that we are fully supportive of desal, when it’s a good project.”

Water districts voiced support for the project, with the Santa Margarita Water District calling it “an important demonstration project to show that small-scale, distributed ocean desalination plants are feasible not only in South Orange County, but also in other areas of … California.”

But a coalition of environmental groups and the Society of Native Nations raised concerns about the environmental impacts and questioned the need for the project, warning that the plant’s discharge could pollute waters frequented by marine life, such as whales and dolphins.

“We cannot afford to further harm the environment; we cannot continue killing marine life, and exposing toxic waste to so many,” they wrote in a letter to the Coastal Commission.

The environmental groups urged the Coastal Commission to consider alternatives, such as increased conservation, stormwater capture and more water recycling, and warned that well intakes planned for Doheny State Park “could impact users and beneficial uses of the Doheny State Park and its adjacent marine waters.”

Rick Shintaku, general manager for the South Coast Water District, agreed that “recycling and conservation will always be the first solution. But if you need additional reliability, as we show in South Orange County, it’s a solution. And it’s a solution that could resolve a lot of the reliability issues that we specifically have in our area.”

What’s next for Doheny plant

Dana Point is known for its tidepools — a sensitive habitat for crabs, mussels, snails, fish and other marine life that is protected under state law. Tidepools in California have been severely damaged by human disturbance, development and climate change.

Before construction can begin, the Doheny plant will need a lease from the California State Lands Commission. Construction is expected to take approximately three years, according to water district spokesperson Sheena Johnson, and the district has already secured more than $32 million in federal and state grants.

The plant is designed to produce 5 million gallons of water per day. Shintaku says his district needs only 2 million gallons per day from the plant — enough to supply about 40% of its drinking water needs. The rest, he said, will likely go to other water agencies: Laguna Beach County Water District and the city of San Clemente have sent letters of interest that the district shared with CalMatters.

The water will be pricier than imported water, the Coastal Commission’s staff report says — costing about 20% more at $1,479 per acre foot. Though “much lower than identified for other recent seawater desalination projects in California,” it’s expected to increase monthly costs by about $2 to $7 per household.

At the hearing today, staff warned that the price estimates are based on a number of uncertain assumptions, including sales of the extra water to external partners that have not yet been identified. “Because of this uncertainty, it’s possible that the cost could be closer to $15 a month per household,” environmental justice analyst Javier Padilla Reyes told the commission, which could affect low-income customers already burdened by pollution.

Staff called for a study on impacts to low-income customers and potential strategies for alleviating them, which Reyes said the water district had agreed to do.

The vote comes as drought continues to grip California and the broader Colorado River Basin, spotlighting the vulnerability of Southern California’s imported water supplies. Desalination offers the possibility of turning salty seawater into drinking water — but its promise has been tempered by concerns about cost, energy demands, and environmental impacts.

Huckelbridge noted that Newsom’s blueprint for bolstering California’s water supply, unveiled in August, included desalination and said that meeting California’s future water needs “will require all the tools in the toolbox.”

But, she added, “as pointed out in the strategy, it is critical that we tackle this crisis in ways that protect our coastal and ocean resources and provide safe and equitable drinking water for all Californians.”

Several desalination facilities already pump out drinking water along California’s coast. But in a high-profile decision in May, the Coastal Commission rejected Poseidon Water’s proposed $1.4-billion plant in Huntington Beach despite California Gov. Gavin Newsom’s vocal support of the project. The rejection came, in part because of risks to marine life and the lack of local demand for the pricey water.

Coastal Commission Executive Director Jack Ainsworth said at the time that the denial of the Huntington Beach project “does not mean that we’re setting the stage for the denial of all desal facilities or other critical infrastructures across the state … every project has a different set of circumstances, facts and context.”