Lake Mead is at its lowest level since the 1930s, when Hoover Dam was built and the lake was first filled in.
Federal officials are preparing to release a new projection on the lake, which currently at 39 percent capacity, according to an Associated Press report.
Lake Mead is currently 1,080 feet above sea level, down almost the width of a football field from its full capacity of 1,225 feet above sea level.
All water deliveries from the lake to Arizona and Nevada will be stopped if its level drops to 1,075 feet above sea level, and at 1,000 feet two drinking water intakes would dry up, according to the report.