Lake Mead has sunk to record-low water levels and officials expect the reservoir to continue dropping.
The reservoir's surface on Wednesday hit its lowest level since its creation in 1935.
Though officials say Lake Mead will likely continue to drop two to three more feet through the end of June, water levels are expected to rebound before the beginning of next year, when jurisdictions would be asked to accept shortages in supply.
Lake Mead provides water to Nevada, California, Arizona and Mexico. Facing a drought of more than a decade, it has dropped 130 feet since 2000, sitting at about 1,074 feet of its 1,221-foot capacity.
The reservoir was last at full capacity in 1983.