Getting plants to grow in the Sonoran Desert is made possible by importing billions of gallons of water each year. Cotton is one of the thirstiest crops in existence, and each acre cultivated here demands six times as much water as lettuce, 60 percent more than wheat. That precious liquid is pulled from a nearby federal reservoir, siphoned from beleaguered underground aquifers and pumped in from the Colorado River hundreds of miles away. Greg Wuertz has been farming cotton on these fields since 1981, and before him, his father and grandfather did the same. His family is part of Arizona’s agricultural royalty. His father was a board member of the Central Arizona Water Conservation District for nearly two decades. Wuertz has served as president of several of the most important cotton organizations in the state. ... But what was once a breathtaking accomplishment — raising cotton in a desert — has become something that Wuertz pursues with a twinge of doubt chipping at his conscience. Demand and prices for cotton have plummeted, and he knows no one really needs what he supplies. More importantly, he understands that cotton comes at enormous environmental expense, a price the American West may no longer be able to afford. ... The federal government has long offered him so many financial incentives to do it that he can’t afford not to. ... “Some years all of what you made came from the government,” Wuertz said. “Your bank would finance your farming operation … because they knew the support was guaranteed. They wouldn’t finance wheat, or alfalfa. Cotton was always dependable, it would always work.” ... The still-blooming cotton farms of Arizona are emblematic of the reluctance to make choices that seem obvious.

A handful of landowners—about 500 farms in all—control the rights to 3.1 million acre-feet a year from the Colorado River. That’s equal to about a third of the water used by California’s cities, with 37 million people, where a four-year drought means neighbors report you if your lawn is green. Or, to measure another way, it’s half again as much water as Governor Jerry Brown aims to save under his April executive order, which set a February 2016 deadline for a 25 percent reduction in urban use. An acre-foot is about 326,000 gallons (1.2 million liters) and can supply the household needs of about 10 people for a year, though actual water use rates vary widely. ... Imperial Valley farmers know their water is precious and understand that to preserve a way of life that runs back a century they have to grapple with the needs of a drought-stricken state. Politicians, regulators, and lawyers have squeezed the valley before to get at its water. In 2003, the Imperial Irrigation District, under pressure from Senator Dianne Feinstein and other federal and state officials, controversially agreed to sell as much as 280,000 acre-feet a year to San Diego. Farmers here still discuss that episode at length, and emotions are still raw, because they believe similar water transfers are likely in the valley’s future. ... “People think transferring water out of the valley is a great sin,” he says. “Wasting water can be an even greater sin.” The neatly prepared field he’s inspecting is perfectly level—he uses lasers to make sure—and slightly lower than adjacent sections so water moves by gravity at an optimal speed. ... The most basic principle governing water use in the western U.S. is this: first in time, first in right. That’s why Imperial Valley farmers have so much water. They arrived early, building the first canal to withdraw Colorado River water and ship it to the valley in 1901. ... More than half the people who own land in the valley today live elsewhere.

Since 1960, tens of millions of people have migrated toward the Pacific, settling in Las Vegas and Tempe and Boulder. Denver has tripled in size. Phoenix, having added some 3.6 million people, has more than quintupled. Today, one in eight Americans depends on water from the Colorado River system, and about 15 percent of the nation’s crops are grown with it. ... the demands on the river were never sustainable. In 1922, the seven states in the Colorado River watershed signed a compact dividing its water. With little historical data, they calculated the river’s capacity after a decade of unusually wet conditions. ... Since the current drought began, in 2000, that shortfall has averaged 25 percent. Instead of adjusting their allotments, states have drawn down the nation’s largest reservoirs, which are quickly draining. Even this winter’s El Niño weather pattern won’t bring enough rain to restore the region’s supply ... To determine who gets water and who doesn’t, states rely on a system that originated more than 150 years ago—when water was plentiful and people were scarce. ... “prior appropriation,” which promised rights to use a share of water based on who got there first. ... Prior appropriation became the foundation of western water law, and it established order in the West. Today, though, state water laws are largely to blame for the crippling shortages. Because water rights were divvied up at a time when few cities existed west of the Mississippi, some 80 percent of the region’s water goes to farmers, leaving insufficient supplies for growing cities and industries. And farmers must put all their water to “beneficial use” or risk losing their allotment—a rule that was originally intended to prevent hoarding but that today can encourage waste. Many farmers have not adopted modern technology that can cut water use by up to 50 percent, in part because they need to protect their water rights. ... Allowing people to buy and sell water rights is a more expedient way to redistribute the West’s water, he argues. Waste would be discouraged, water would shift to where it’s needed most, and farmers would be compensated. ... The West would have plenty of water if people used it more wisely: Most of the region’s supply goes to growing low-value, water-intensive crops such as hay and alfalfa—in many cases in the desert.

If Las Vegas is the most profligate place on earth, where chance is king and the future is routinely gambled away, it is also possibly the most frugal and forward-looking American city in one respect: water. And now it’s trying to leverage that reputation by turning itself into a hub for new and innovative water technology. ... In the thirstiest city in the nation’s driest state (it gets just 4 inches of rain a year), water is the last thing Las Vegas wants to gamble on. After 16 years of drought, water levels in nearby Lake Mead, the city’s primary water source, have dropped so precipitously that white rings have formed on its banks. Las Vegas, like a bankrupt gambler who suddenly realizes that things have to change, has responded with a host of water conservation measures. ... The water industry is by nature risk averse, since a mistake can have catastrophic health consequences (see Michigan; Flint). But with more pressure on water supplies around the United States and the world, innovation is increasingly important. Las Vegas’ focus on water—and the constant pressure on its supply—has driven years worth of public experimentation, establishing the area’s umbrella water utility, the Southern Nevada Water Authority, as a nationally recognized leader in water quality treatment. The utility boasts a state-of-the-art laboratory that produces ground-breaking research and a roster of scientists who routinely publish in major academic journals.