The Claude “Bud” Lewis Carlsbad Desalination Plant offers an environmentally responsible water supply in an era of increasing water scarcity, according to results of a new scientific study being released next week at a statewide conference of desalination experts.

The report – the largest environmental assessment to date of the nation’s largest seawater desalination plant – also highlighted the comprehensive monitoring requirements in place for desalination plants in California to demonstrate how nearshore waters remain healthy.

“The most robust monitoring program of the area ever completed demonstrated the Carlsbad Desalination Plant is operating in compliance with all applicable regulations and permits in harmony with the coastal marine environment,” said the study, prepared by Miller Marine Science & Consulting, Inc. of Aliso Viejo.

To date, the desal plant has produced more than 124 billion gallons of high-quality drinking water for the San Diego region. The Miller Marine report was a requirement of the plant’s discharge permit and evaluates four years of extensive environmental monitoring conducted between 2019 – 2023.

The Carlsbad Desalination Plant is the largest, most technologically advanced and energy-efficient desalination plant in the nation, and it has provided a sustainable water supply to residents and businesses in San Diego County since December 2015. Photo: San Diego County Water Authority

“This study shows how seawater desalination can provide a new and reliable supply of water with minimal impacts to aquatic life. That’s a win for our region and the environment,” said Dan Denham, San Diego County Water Authority General Manager.

The Carlsbad Desalination Plant minimizes the San Diego region’s vulnerability to statewide drought conditions. It is part of a $1 billion project that includes the nation’s largest, most technologically advanced and energy-efficient seawater desalination plant, a 10-mile large-diameter pipeline, and improvements to Water Authority facilities for distributing desalinated seawater throughout San Diego County.

Next week, the Miller Marine report is being discussed during the annual conference of CalDesal, an industry association that brings together water leaders to discuss a range of issues related to seawater and groundwater desalination. For more about the conference, click here.

Among the study’s findings were:

• The Carlsbad coastal marine environment continues to support its full suite of beneficial uses.
• The Carlsbad Desalination Plant’s discharge is not disturbing the receiving water quality or environment outside the brine mixing zone.
• The Carlsbad Desalination Plant is not discharging toxic substances to the detriment of the environment. The plant’s operations result in an environmentally safe discharge to the marine environment in compliance with all regulations.

The desal plant provides several environmental benefits by offsetting carbon emissions, employing cutting-edge technology to reduce and recapture 46% of energy consumption during desalination, and restoring extensive coastal wetlands to benefit native fish, wildlife, and plant species within South San Diego Bay.

To read the full study, click here.