In this March 11, 2015, file photo, a worker climbs stairs among some of the 2,000 pressure vessels used to convert seawater into fresh water through reverse osmosis in the western hemisphere's largest desalination plant in Carlsbad, Calif. The International Monetary Fund issues its annual checkup of the American economy on Thursday, June 4, 2015.
In this March 11, 2015, file photo, a worker climbs stairs among some of the 2,000 pressure vessels used to convert seawater into fresh water through reverse osmosis in the western hemisphere's largest desalination plant in Carlsbad, Calif. The International Monetary Fund issues its annual checkup of the American economy on Thursday, June 4, 2015. Gregory Bull AP
In this March 11, 2015, file photo, a worker climbs stairs among some of the 2,000 pressure vessels used to convert seawater into fresh water through reverse osmosis in the western hemisphere's largest desalination plant in Carlsbad, Calif. The International Monetary Fund issues its annual checkup of the American economy on Thursday, June 4, 2015. Gregory Bull AP