As the Southwest dries, can a city infamous for luxury find a way to exist with less? Anything goes in Las Vegas, except excessive water use.

Two decades ago, the city began to face a truth that many other places in the Southwest were attempting to put off: Eventually, it could run out of water.

In contrast with towns like Phoenix or Los Angeles, which get water from a number of sources, Las Vegas still gets roughly 90 percent of its water from the Colorado River, and it has little additional water to tap into.

By the time the river hit a record low in 2002, Las Vegas had begun pursuing strong water-saving measures to meet population expansion and adapt to a dwindling river.

The city known for excess and summer pool parties began counting every drop, even the tiniest dribbles spilling into asphalt. “We couldn’t have made additional water commitments,” says John Entsminger, the Southern Nevada Water Authority’s general manager—no more residences, no more casinos, no population expansion at all.