Lake Mead's water level fell to 1,040.5 feet on Friday. It has continued to fall every day this month, the Bureau of Reclamation reported.

The largest reservoir in the United States has tumbled to a record low level as drought, extreme heat, a dearth of snow and a heavy water demand imperil the Colorado River system.

The Colorado River basin is a critical system for residents in the western U.S. and Mexico.