Kylan Frye steers her Subaru station wagon along the slushy roadways of the Farmington Bay Waterfowl Management Area at the edge of Utah’s Great Salt Lake. It’s a February afternoon, gray and cold, and a layer of snow covers the wetlands that spread for miles around us. The Wasatch Range rises ruggedly in the background, but otherwise it feels like we’re driving through a barren white sea, indistinguishable from the pale sky if not for the occasional dots of sagebrush, sedge, and cottonwood. The air is thick with gull calls and the periodic flash of a great blue heron gliding by.

Frye, a conservation biologist at HawkWatch International, parks the car. Millions of birds use the Great Salt Lake to breed, feed, and rest, but there’s one in particular that I’m eager to see. The lake supports one of the top 10 winter populations of bald eagles in the continental United States—more than 500 birds whose habitat could be jeopardized by Utah’s ever-growing thirst for water.

We get out. With us is Zach Frankel, a biologist who runs the nonprofit Utah Rivers Council. Together, we look over the bay toward the mountains. At a break in the ice, dozens of gulls and northern pintail ducks have gathered. Behind them, standing still and alone, is something larger but hard to distinguish at this distance.

“Is there an eagle out there?” Frankel asks, pointing to the solitary bird.

“Might be,” Frye says. “They’re kind of all over.” She pulls out a spotting scope, a slipper-shaped magnifier that mounts on a tripod. Through the powerful lens, the eagle comes into focus: Posed elegantly against the alpine backdrop, it looks back over its shoulder like a Renaissance model waiting to be painted. This is the first eagle I’ve ever seen in the wild, and catching a glimpse of our national symbol socks me with a sudden surge of patriotism.

“The bald eagles are a success story of the Endangered Species Act,” Frye tells us. Reduced to 400 breeding pairs in the lower 48 states in 1963, the raptors became the target of an aggressive conservation effort that included habitat protection, captive breeding, and a ban on the shell-thinning insecticide DDT. By 2007 the population had rebounded to 10,000 pairs and the eagles were removed from the government’s list of threatened and endangered species.

But Frankel, who arranged this trip, is worried nonetheless. The Great Salt Lake borders a fast-growing metropolitan area that sprawls for more than 40 miles on either side of Salt Lake City, from Ogden in the north to Provo in the south. The Wasatch Front, as it’s called, houses two million people, the majority of Utah’s population. Its arid climate, cheap water rates, and green lawns mean its residents use extraordinary amounts of residential water—more, Frankel says, than the environment and its creatures can really spare. Now Utah officials say they need more sources of water to keep pace with growth. They’re eyeing the nearby Bear River, which (along with its tributaries) supplies 60 percent of the fresh water flowing into the Great Salt Lake. If the Bear is tapped, Frankel says, the shallow lake could see its levels drop by as much as 4 feet during dry years, shrinking the wetland habitat available to eagles and other birds.

“These birds fly thousands of miles and drop down exhausted on the Great Salt Lake to feed,” he says. Without sufficient water, “you will see a reduction in their food supply. You’ll see more crowding. You’ll see higher mortality rates from disease. The raptors that come here will lose their prey base. We’re concerned that we’re going to see millions of birds die off across hundreds of species.”

And Utah is hardly alone. Across the country, population growth and climate change are putting stresses on water supplies that we once took for granted (and often still do). Americans accustomed to blithely running bathtubs or garden hoses are discovering that existing sources are limited. Tapping new sources could have troubling consequences, which is why we need to stop thinking of water as cheap and infinite.

The history of the American frontier might appropriately be subtitled The Great Human Conquest of Water. The Mormon pioneers who migrated to Utah in the mid-19th century hunkered down in what was not exactly an obvious place to build a civilization. “Nonetheless, within hours of ending their ordeal, the Mormons were digging shovels into the earth beside the streams draining the Wasatch Range, leading canals into the surrounding desert which they would convert to fields that would nourish them,” Marc Reisner wrote in his 1986 book Cadillac Desert. “The Mormons attacked the desert full-bore, flooded it, subverted its dreadful indifference—moralized it—until they had made a Mesopotamia in America.” The dams and aqueducts that later sprung up throughout the West allowed us to build cities in places that previously seemed hostile to human settlement—Las Vegas, Phoenix, Denver, Los Angeles—along with sprawling farm operations in California’s San Joaquin Valley and elsewhere.

The West’s system of water governance was designed to ensure that everyone had enough. It assigned senior rights to the first arrivals, some of whose descendants today grow low-value, water-intensive crops like cotton, rice, and alfalfa. Those rules reflected a smaller, more rural America—before the growth of metropolises, before the modern industrial economy, before the coining of the term global warming. “In effect, we’re managing 21st-century challenges with 19th-century policies,” says Peter Gleick, president of the Pacific Institute, a California-based research group that specializes in water and sustainability. In some places, “we’ve given away too much water—more water than nature seems like it’s going to reliably provide us.”

Those decisions are catching up with us. Ten years ago, the U.S. General Accounting Office asked state water managers about their future concerns. Of the 47 states that responded, 36 predicted shortages by 2013 under normal conditions, 46 under drought conditions. Their forecasts proved prescient. In the Colorado River Basin, which encompasses seven states and is home to 40 million people, a government report released last December says demand could dramatically outstrip supply by 2060. The river’s two largest reservoirs, Lake Mead and Lake Powell, stand a 50-50 chance of running dry by 2021—if we do nothing to address dwindling resources, says another study by scientists at the Scripps Institution of Oceanography at the University of California, San Diego. (The basin includes parts of Utah but not the Salt Lake area.)

And the West doesn’t hold the monopoly on problems. “Increasingly, we are running into absolute limits on water supply—in lots of places, not just in places we’ve traditionally thought of as arid or dry,” says Gleick. Georgia, Alabama, and Florida, for example, have been battling among themselves over two river basins. Landlocked Atlanta wants the water for its drinking supply, while Florida and Alabama insist they need it both for human consumption and to support fish and shellfish populations.

Some researchers call the word shortage a misnomer. Even in the most overstretched areas, we turn on the tap and water comes out. The real problem comes from assuming we can proceed as we always have, that we don’t need to make adjustments to accommodate growing populations and diminishing resources. “It’s not that we don’t have enough water,” says Scripps Institution climate scientist David Pierce, who coauthored the Lake Mead study. “We don’t have enough to continue as we’ve been doing, with a lot of irrigated crops in the dry regions and rapidly growing cities.”

There’s another complicating factor: the acceleration of climate change. Scientists say higher temperatures will cause more evaporation and alter the slow, steady snowpack melts that provide much of the West’s water. Droughts will become more common too. Meanwhile, demand will increase as farmers and gardeners try to grow the same plants in hotter, drier conditions. A study by the consulting firm Tetra Tech, commissioned by the Natural Resources Defense Council, predicts that 1,020 U.S. counties, mostly in the Great Plains and Southwest, face high or extreme water-shortage risks by 2050 in large part because of climate change.

These forces seem epic and beyond our control. But the stresses on our water are also the product of what we all do in our cities and suburbs: how we price water, how we use it, and how we waste it.

In 2010 the research group Circle of Blue compared how much water residents of 23 U.S. cities consumed. The spread was ample, from 211 gallons per person daily in Fresno, California, to 41 gallons in Boston. Coming in second highest, at 180 gallons, was Salt Lake City. Drive around its neighborhoods and the reason becomes evident: Utah’s capital is a city of front lawns—mile after mile of lots covered with thirsty turf grass. Two-thirds of Utah’s residential water is used outdoors, according to the state’s Division of Water Resources, and in some counties the percentage is much higher.

Carving out paradise from the desert is a deeply rooted tradition. “The people that settled here came from places that were much wetter than Utah is,” says Eric Millis, the division’s deputy director. “They wanted to make things comfortable, and there was water available, so they put in lawns.” Other arid cities, like Tucson and Santa Fe, came to embrace the low-water landscaping technique called xeriscaping. But in Salt Lake City, along with the rest of Utah, big green yards “have endured as part of the culture,” Millis says.

Lawns are water hogs. “When you use water indoors, most of it goes down the drain, and it goes to a sewer system, and it goes to a treatment plant. Unless you’re in a coastal environment, that water is then put back in a stream and someone can use it again,” says Douglas Kenney, director of the Western Water Policy Program at the University of Colorado’s Natural Resources Law Center. “When you put water on your lawn, not only is it a lot of water, but that’s water that doesn’t come back in any way.”

If history and tradition encourage lush greenery, economics makes it possible. At the time of Circle of Blue’s survey, a family of four consuming 600 gallons a day paid $224 monthly in Santa Fe, $73 in Tucson, and $33 in Salt Lake City. That’s because Utah municipalities often subsidize residential water with property taxes. Millis says this system provides a steady, predictable income for water districts. But it also keeps user fees artificially low, masking the true cost of water. “The higher the price, the more people pay attention,” says the Pacific Institute’s Gleick, who notes that water bills are often lower than Internet and telephone bills. “If water is cheap and there’s no incentive to conserve, then people don’t conserve.” Some cities have built inducements into their rate structures: In Seattle and Tucson, for example, the price of a gallon rises steeply as consumption goes up. In Utah districts, not only is water inexpensive; its pricing also remains relatively flat, even for the most extravagant users.

Utah does encourage conservation, most notably through an educational program called “Slow the Flow.” And as farms have turned into subdivisions, some districts have acquired agricultural water to convert to municipal use. But Millis, the deputy director, says these measures alone won’t free up enough water to accommodate the Wasatch Front’s future growth. That’s why the state plans to spend $1.5 billion to dam and pipe water from the Bear River, the Great Salt Lake’s biggest tributary, by 2035. Millis says the state’s models show the project will cause only a minor drop in the lake’s levels. “It will suck the lake in some—more than you might expect,” he says. “But we believe that shorelines would adapt.”

Frankel of the Utah Rivers Council isn’t so sure. The Bear River is already expected to lose between 5 and 18 percent of its flow to climate change; funneling away even more to nourish suburban lawns could spell “the end of the West’s last great wetland ecosystem,” he says. Not only that: Damming the Bear could flood Northwestern Shoshone ancestral lands, as well as historic farms and ranches.

Frankel takes me to Tremonton, 75 miles north of Salt Lake City, where we meet three generations of a ranching family called the Selmans. Fred and Laura Selman, who are close to retirement age, live in a neat brick house overlooking the Bear River, on part of a 23,000-acre ranch that includes roaming grounds for 2,900 breeding ewes. (“Sheep are like gypsies,” Laura explains to me.) The Selmans, who also raise beef cattle, have been honored for their conservation practices: planting lines of trees called windbreaks, for example, which protect not only livestock but also wildlife and birds. “The land is a living thing,” says their 45-year-old son Bret. “Stewardship is a sacred calling.” Asked how often he thinks about conservation, Bret responds, “How often do you breathe?”

Even when grandson Cole went on his Mormon mission to Mexico, he couldn’t stop thinking about the land. Bret would send him text messages: Today we sheared the sheep; today we branded the calves; here’s a photo of a pine tree from the top of the mountain. Reading the messages, Cole would feel the sensation of hard work in his muscle memory and long to be home. Once, locating the ranch on Google Earth while in Mexico, Cole saw an aerial view of his family’s sheep on their twice-a-year migration across a certain footbridge. “You start getting all emotional,” says the 24-year-old.

Bret and I climb into his truck. In the late afternoon light, the mountains glow a pale orange. We drive past cylindrical bins filled with corn and barley, stacked bales of hay, and yearling calves sheltered by piles of snow. “Everything’s sleeping,” Bret says, just before a flock of Canada geese fly by. They circle and squawk before landing for the night. “They’re putting on a show for you,” he says. “I love watching them fall out of the sky like that.”

Losing this heritage is inconceivable to Bret. His family has been farming in Utah since the 1890s and fighting the Bear River Development since the 1990s, when a dam site was proposed that would have flooded the Selman’s 340-acre home ranch. That site was shelved—for the moment—and no one knows today whose land might be inundated. But it mystifies Bret that any productive farm or ranchland might be sacrificed before every other possible solution to the Wasatch Front’s water needs is explored. “So people can have green lawns, we give up agriculture? That doesn’t make sense to me,” he says. “Utah can’t feed itself now because of population increase and farmland losses. How much more ground do we want to lose?”

Ensuring enough water for a growing America will require everyone to pitch in. Farmers will need to reevaluate their crop choices and use more efficient irrigation technology. (Many have done so already.) Cities and suburbs will need to adopt rate structures that reflect water’s true cost and penalize inefficiency. They’ll also need to step up their education efforts.

There are plenty of models to follow. Some communities have created a buzz with xeriscaping contests that reward homeowners and professionals who design beautiful low-impact gardens. Others, such as San Diego and Las Vegas, offer rebates to residents who tear up their lawns and replace them with xeriscapes. Tucson reimburses residents who set up systems to harvest rainwater, and who irrigate their gardens with “gray water” recycled from bathtubs and clothes washers.

Tucson, which consumed residential water at about half the rate of Salt Lake City in the Circle of Blue survey, is a good example of what happens when a city collectively adopts a conservation ethic. “For many years, Tucson was entirely dependent upon a groundwater aquifer that was declining rather rapidly,” says Kenney of the Western Water Policy Program. “So Tucson has long been very fearful of running out of water. That created a culture where people just didn’t feel comfortable wasting water. If you put a lawn in your property in Tucson, you can expect some pushback from your neighbors.” That pushback rarely needs to happen: Newcomers usually see their neighbors’ desert landscapes and adjust automatically. “It’s very strange to drive through a neighborhood and see any lawn,” says Fernando Molina, a spokesman for Tucson Water. “People are proud of that as a community.”

Tucson has taken ownership of its water problems. That’s what Americans everywhere need to do: recognize that good decisions now can prevent economic and environmental upheaval down the road. Surviving the 21st century will mean changing how we all view and use water—treating it like the precious resource it has always been.