AUDIE CORNISH, HOST:
It's the rainy season in Mexico. Most afternoons, thick clouds roll into Mexico City's mountain-ringed valley. The skies darken, and then they open.
(SOUNDBITE OF RAINFALL)
CORNISH: Despite the rain fall, many of Mexico City's more than 20 million residents don't have enough water to drink. Nearly all that rain runs off concrete-covered streets into a drainage system built to avoid flooding. Drinking water increasingly comes from a vast aquifer under the city. And as that water table drops, the city sinks. All this week, we're talking about water - who's got it and who doesn't. Today NPR's Carrie Kahn takes us to Mexico City.
CARRIE KAHN, BYLINE: This sprawling megalopolis sits more than 7,000 feet above sea level in a mountain-ringed valley that fills like a plugged up bathtub when it rains.
RAMON AGUIRRE DIAZ: (Speaking Spanish).
KAHN: "It's a historic mistake the city has had to pay for for more than 500 years," says Ramon Aguirre Diaz, who's run Mexico City's water system for more than a decade. While the Aztecs first built the city here, Aguirre says it was Hernan Cortes and his band of conquerors in the 1600s who did the initial damage, draining the vast lakes that once filled this large valley. By the 20th century, not much surface water survived as the city kept growing. These days, water is piped in over hundreds of miles, filling 30 percent of the city's freshwater needs. The rest comes from Mexico City's vast underground aquifer. Today, Aguirre says twice as much water is pumped out of there than is put back in.
DIAZ: (Speaking Spanish).
KAHN: "We are depleting volumes of water that took hundreds, thousands of years to store. Sooner or later, it will run out," he says. When exactly that is, no one really knows. But for those living in the poorer eastern stretches of the city like Marco Marquez, it feels like now.
MARCO MARQUEZ: (Speaking Spanish).
KAHN: "Look," he says, spinning a tap of his water faucet, nothing "- not even a drop." During the rainy season, he gets about an hour of water a day. His tiny patio is crammed with all sizes of storage containers filled with water. During the dry season, he says he can go two, even three months without water. Sometimes he says the government sends in water trucks, known as pipas.
MARQUEZ: (Speaking Spanish).
KAHN: "The quality of that water is terrible. It's disgusting," he says. "You can only use it to flush the toilets or wash the sidewalk." These days, more and more people in the city depend on pipas for their water. The city's underground pipes, half of which are at least 60 years old, fail at an alarming rate. Water from trucks like Juan Flores' is in high demand.
JUAN FLORES: (Speaking Spanish).
KAHN: He's on top of a 2,600-gallon tanker, filling up at a city-run station where the water is pumped directly out of the aquifer. In many ways, it's a much more efficient system. The city's pipes are so prone to breaks and leaks that nearly 40 percent of the potable water is just wasted. That inefficiency, along with urban sprawl and hotter weather due to climate change, has put even more demand on the overexploited aquifer. And as the water table drops, so does many parts of the city - on average, about eight inches a year, even more in some spots. As the earth sinks, it leaves buildings tilting, roadways buckling and pipes rupturing or buckling backward.
MARIA ESTELLA ISLA: (Speaking Spanish).
KAHN: Check out the patio of 42-year-old Maria Estella Isla's house where she just started a load of laundry. She hasn't had water in days. She fills her washing machine with water she scoops out of a huge blue plastic storage barrel.
ISLA: (Speaking Spanish).
KAHN: "Look at my patio. It's full of cracks." A huge fissure runs right through her property out the gate and down the street. One half of the block has sunk. It's at least a foot lower than the other side. The underground sewer line connected to her house now tilts upward and floods her patio, especially on rainy days.
Since the 1900s, the city has spent billions on flood control. The latest project already topping $2 billion is plagued with cost overruns and delays and will do little to help the city's water shortage or sinking problems. It just moves the water, rain and sewer discharge out of the city as fast as it can. Eighty percent of rain water flushes through those pipes. Little is recycled or used to recharge the aquifer. Water administrator Ramon Aguirre says there's no time to waste in fixing the system.
DIAZ: (Speaking Spanish).
KAHN: "The city just won't make it to the 22nd century," he says, "if we don't resolve this problem and resolve it soon." Carrie Kahn, NPR News, Mexico City. Transcript provided by NPR, Copyright NPR.