Well bore construction and design is highly regulated and technically robust. Groundwater is permanently protected by several layers of steel casing (pipe) and cement, as well as thousands of feet of rock. A 2011 Groundwater Protection Council study found well failure to be extremely rare in Texas (less than 0.01 percent).
According to U.S. Department of Energy report, “Groundwater is protected during the shale gas fracturing process by a combination of the casing and cement that is installed when the well is drilled and the thousands of feet of rock between the fracture zone and any fresh or treatable aquifers.”
“To my knowledge, I still have not seen any evidence of fracking per se contaminating groundwater,” says Energy Secretary Ernest Moniz.
Read more about scientific studies that confirm fracking does not contaminate water.