Pavillion, Wyoming

There are few things a family needs more than fresh drinking water. And Louis Meeks, a burly Vietnam War veteran with deep roots in the central Wyoming grasslands, had abundant water on his 40-acre alfalfa farm, which is speckled with apple and plum trees, on a rural dirt road five miles from the town of Pavillion. For 35 years, he drew it clear and sweet from a well near the front door of the plain, eight-room ranch house that he and his wife, Donna, own. The water was so good that neighbors used to pull off the road to fill plastic jugs for themselves.

But in the spring of 2005, Meeks' water turned fetid. His tap ran cloudy, and the filmy water shimmered with rainbow swirls. The scent was sharp, like gasoline. When he ran the pump for 20 minutes, the pipes would shudder and run dry.

The area's complicated geology includes some pockets of bad water, but Meeks suspected a different cause: industrial pollution. Pavillion lies in the middle of Wyoming's huge gas patch, which has thousands of  wells. Since the mid-1990s, more than 200 gas wells have been drilled right around the tiny town, which is home to 174 people. The drilling has left abandoned toxic waste pits scattered across the landscape. But Meeks believed the gas wells themselves were to blame. They extend far underground, considerably below his water well, which was a couple of hundred feet deep. The more Meeks learned, the more he was alarmed by one especially controversial step in the drilling process. The industry calls it hydraulic fracturing: the high-pressure injection of water and a brew of chemicals into a well to break apart rock formations and release the gas inside them.

The "fracking" process has spurred a natural gas rush that extends from New Mexico all the way to New York state. Gas has become a fashionable fuel that generates about one-fifth of the nation's electricity and heats about half of its homes. Fracking is even used for new oil wells in geologically challenging landscapes like the Bakken Formation in North Dakota and eastern Montana. But as Meeks would discover, no one really knows how far the chemicals spread underground when a well is fracked.

Three months before Meeks' water went bad, EnCana Oil & Gas USA Inc. -- one of North America's largest oil companies -- had laid pipe down Tribal Pavillion 24-2, a gas well about 500 feet from Meeks' house. EnCana said neither the drilling nor the fracking of 24-2, one of its many local gas wells, could have polluted Meeks' water well because the layer of natural gas was some 3,200 feet below the bottom of Meeks' well. The underground separation should have insulated Meeks' water supply from the gas well, the company said. However, in what it describes as a "good neighbor" gesture, EnCana began delivering a tanker truckload of fresh water to Meeks each month. State environmental officials provided little help, telling Meeks that his well water met national standards and was still safe to drink. The taste, they said, was probably from rare iron bacteria that can't easily be removed. But Meeks remained unconvinced, and his neighbors shared his worry: They stopped filling up their bottles with his water and even hesitated to touch it.