The Last Drop

We may not get all the water we want. But we can have the water we need.

This story appears in the April 2010 issue of National Geographic magazine.

Living in the high desert of northern New Mexico, Louise Pape bathes three times a week, military style: wet body, turn off water, soap up, rinse, get out. She reuses her drinking cup for days without washing it, and she saves her dishwater for plants and unheated shower water to flush the toilet. While most Americans use around a hundred gallons of water a day, Pape uses just about ten.

"I conserve water because I feel the planet is dying, and I don't want to be part of the problem," she says.

You don't have to be as committed an environmentalist as Pape, who edits a climate-change news service, to realize that the days of cheap and abundant water are drawing to an end. But the planet is a long way from dying of thirst. "It's inevitable that we'll solve our water problems," says Peter Gleick, president of the Pacific Institute, a nonpartisan environmental think tank. "The trick is how much pain we can avoid on that path to where we want to be."

As Gleick sees it, we've got two ways to go forward. Hard-path solutions focus almost exclusively on ways to develop new supplies of water, such as supersize dams, aqueducts, and pipelines that deliver water over huge distances. Gleick leans toward the soft path: a comprehensive approach that includes conservation and efficiency, community-scale infrastructure, protection of aquatic ecosystems, management at the level of watersheds instead of political boundaries, and smart economics.

Until the mid-1980s, the city of Albuquerque, some 60 miles southwest of Pape's home in Santa Fe, was blissfully unaware that it needed to follow any path at all. Hydrogeologists believed the city sat atop an underground reservoir "as big as Lake Superior," says Katherine Yuhas, conservation director of the Albuquerque Bernalillo County Water Utility Authority. The culture was geared toward greenery: Realtors attracted potential home buyers from moist regions with landscaping as verdant as Vermont; building codes required lawns. But then studies revealed startling news: Albuquerque's aquifer was nowhere near the size it once appeared to be and was being pumped out faster than rainfall and snowmelt could replenish it.

Duly alarmed, the city shifted into high gear. It revised its water-use codes, paid homeowners to take classes on reducing outdoor watering, and offered rebates to anyone who installed low-flow fixtures or a drip-irrigation system or removed a lawn. Today Albuquerque is a striving example of soft-path parsimony. Across the sprawling city, a growing number of residents and building owners funnel rainwater into barrels and underground cisterns. Almost everyone in town uses low-flow toilets and showerheads.

These efforts have shrunk Albuquerque's domestic per capita water use from 140 gallons a day to around 80. The city "anticipates another 50 years of water, economically and sustainably supplied, even with a growing population," says Yuhas. After that there's the option to desalinate brackish water nearby and new technologies such as dual plumbing: one set of pipes to deliver highly treated potable water and another to recycle less treated water for flushing toilets, watering lawns, and other nonpotable uses. Albuquerque already uses wastewater—from treatment plants and from industry—to irrigate golf courses and parks. Other municipalities have gone a step further and collect wastewater—yes, from toilets—filter and disinfect it to the nth degree, then pump it back into the local aquifer for drinking. There are similar schemes worldwide: Beijing reportedly aims to reuse 100 percent of its wastewater by 2013.

Industry, too, is adapting to less certain water supplies. Frito-Lay will soon recycle almost all its water at its plant in Casa Grande, Arizona; Gatorade and Coca-Cola remove the dust and carton lint from beverage containers using air instead of water; and Google recycles its own water to cool its giant data centers.

This is all reassuring—until you remember that irrigated agriculture accounts for 70 percent of the fresh water used by humans. Given this outsize proportion, it seems obvious that farmers have the greatest potential to conserve water.

Standing on the banks of a trickling ditch, Don Bustos—sunbaked and thickly bearded—demonstrates how he irrigates 130,000 dollars' worth of produce on 3.5 acres north of Santa Fe. "I lift this board"—he points to a plank that forms a gate in the ditch—"and I shove in a stick to hold it up." Gravity does the rest.

For 400 years farmers in the arid Southwest have relied on such acequias—networks of community-operated ditches—to irrigate their crops. The acequia diverts water from a main stream, then further apportions the flow through sluiceways into smaller streams and onto fields. "Without the acequia, there would be no farm," Bustos says. He's also built a water tank with drip-irrigation hoses that feed some of the acequia water directly to the plant roots—and cut his water use by two-thirds as a consequence.

Elsewhere, forward-thinking farmers have replaced flood irrigation with micro-sprinkler systems, laser leveled their fields, and installed soil-moisture monitors to better time irrigation. In California, says the Pacific Institute, such improvements could potentially conserve roughly five million acre-feet of water a year, enough to meet the household needs of 37 million people. Unfortunately, most farmers lack the incentive to install efficient but expensive irrigation systems: Government subsidies keep farm water cheap. But experts agree that more realistic water pricing and improved water management will significantly cut agricultural water use. One way or another, the developed world will get the water it needs, if not the water it wants. We can find new supplies—by desalinating water, recycling water, capturing and filtering storm water from paved surfaces, and redistributing water rights among agriculture, industry, and cities. Cheaply and quickly we can slash demand—with conservation and efficiency measures, with higher rates for water wasters, and with better management policies.

What about the rest of the world? In places lacerated by poverty, the problem is often a lack of infrastructure—wells, pipes, pollution controls, and systems for disinfecting water. Though politically challenging to execute, the solutions are fairly straightforward: investment in appropriately scaled technology, better governance, community involvement, proper water pricing, and training water users to maintain their systems. In regions facing scarcity because of overpumped aquifers, better management and efficiency will stretch the last drops. Farmers in southern India, for example, save fuel in addition to water when they switch from flood to drip irrigation; other communities landscape their hillsides to retain rainwater and replenish aquifers.

Still, the time is coming when some farmers—the largest water users and the lowest ratepayers—may find themselves rethinking what, or if, they should plant in the first place. In the parched Murray-Darling Basin of Australia, farmers are already packing up and moving out.

It is hardly the first time that water scarcity has created environmental refugees. A thousand years ago, less than 120 miles from modern-day Santa Fe, the inhabitants of Chaco Canyon built rock-lined ditches, headgates, and dams to manage runoff from their enormous watershed. Then, starting around A.D. 1130, a prolonged drought set in. Water scarcity may not have been the only cause, but within a few decades, Chaco Canyon had been abandoned. We hardly need reminding that nature can be unforgiving: We learn to live within her increasingly unpredictable means, we move elsewhere, or we perish.