Claude "Bud" Lewis Carlsbad Desalination Plant.
Claude “Bud” Lewis Carlsbad Desalination Plant is named after a former Carlsbad mayor. Photo via

The Claude “Bud” Lewis Carlsbad Desalination Plant has served more than 100 billion gallons of water over the past seven years — a milestone reached in late October, the San Diego County Water Authority and plant owners announced Tuesday.

The plant, which produces 50 million gallons of drinking water daily, enough for 400,000 homes meeting 10% of San Diego County’s water demand, is the largest in the United States.

“As we mark this achievement, water from the seawater desalination plant continues to reduce our dependence on imported water sources, which has the effect of making more water available for drought-stricken communities elsewhere,” said Mel Katz, board chair of the Water Authority.

Desalination uses reverse osmosis technology to remove water molecules from seawater. Water from the ocean is forced through tightly-wrapped, semipermeable membranes under very high pressure. The membranes allow the smaller water molecules to pass through, leaving salt and other impurities to be discharged from the facility.

The plant is a key piece of the region’s multi-decade strategy to diversify its water supply portfolio as California enters a fourth consecutive year of severe drought, officials said.