Project Overview

The Claude "Bud" Lewis Carlsbad Desalination Plant is a 50 million gallon per day (56,000 acre-feet per year (AFY)) seawater desalination plant located adjacent to the Encina Power Station in Carlsbad, California. Desalination has evolved into a desirable water supply alternative by tapping the largest reservoir in the world - the Pacific Ocean. The technology, available for decades, is at work in many arid areas of the world including the Middle East, the Mediterranean and the Caribbean. A 30-year Water Purchase Agreement is in place between the San Diego County Water Authority and Poseidon Water for the entire output of the plant. The plant has been delivering water to the businesses and residents of San Diego County since December 2015.


  • $1 Billion Desalination Plant, Hailed as as Model for State

    Los Angeles Times

    Carlsbad, CA (December 15, 2015) - With Monday's ceremonial opening of the Western Hemisphere's largest ocean desalination plant, a new era began for water use in San Diego County — and possibly for the entire parched state. Read more. 

  • 'Bud' is No. 1 Wonder of North County

    San Diego Union Tribune 

    Carlsbad, CA (December 15, 2015) -

    Water flowing underground — Talking Heads

    At Monday’s symbolic faucet-turning in Carlsbad, the mood was triumphal. Instead of emptying magnums of bubbly, however, the celebrants filled fancy plastic bottles with drinking water and carried them home as if H20 was actually Au, which in the Golden State it sort of is. Read more. 

  • Reporter Traces History of Desalination Project

    San Diego Union Tribune

    Carlsbad, CA (December 14, 2015) - In addition to covering life sciences for The San Diego Union-Tribune, Bradley J. Fikes has written about drought and other water issues. In today’s Back Story, he talks about his SD In Depth story about the significance of the new Poseidon desalination plant in Carlsbad.Question: There have been lots of stories written over the years about the Poseidon undertaking. Read more. 

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State, regional and local water plans all have confirmed that immediate and pressing water needs cannot be accomplished without some investment in seawater desalination.

  • The plant will provide 56,000 AFY of new water supply for the San Diego region. A region where nearly 85% of the current water supplies are imported.
  • The CA Department of Water Resources’ 2009 Water Plan Update identifies the need for 275,000 AF of desalinated water by 2025.
  • The Metropolitan Water District of Southern California’s Integrated Water Resources Plan identifies a need for 150,000 AFY of seawater desalination (including 56,000 AFY from the Carlsbad project) by the year 2020.
  • The San Diego County Water Authority’s (SDCWA) Urban Water Management Plan identifies a need for 56,000 AFY of seawater desalination from the Carlsbad project by 2016.