Can’t imagine how much water it takes for the population there.
Check this out:

For years, experts have been warning people in the American West they will have to make do with less water in the future. That dryer future already may have arrived.

This year, for the first time in history, lower flows in the Colorado River have prompted the federal government to reduce the amount of water flowing into Lake Mead reservoir outside Las Vegas. Bureau of Reclamation officials say if the river’s level doesn’t increase soon, there’s a 50 percent chance that by next year, residents in Arizona, southern Nevada and California will have to start rationing water.