Between Las Vegas and Arizona, Lake Mead, the body of water that is fed by the Colorado River, dropped below 1,075 feet on Tuesday. The low water marks are signaling what could be the first-ever water shortage on the Colorado River, CNN reports.

The lake’s levels show a continuing decline, according to the U.S. Bureau of Reclamation (USBR), and any hope of recovery won’t happen until at least the end of 2022.