Could hydraulic fracturing (fracking) contaminate drinking water aquifers?

No. Each fracture stage is individually engineered and controlled to limit fractures to the oil and gas-bearing rocks. It is also physically impossible for fractures to extend more than 150 metres either side of a well (and even less vertically) because of the high pressures found in rocks at those depths. Extensive research on hundreds of wells in the US has conclusively demonstrated that the fractures induced by the process are confined to the rocks close to the target zone.

In many parts of the US, shales hold both water and natural gas. The presence of methane in these areas’ water supplies is not related to the natural gas industry. Some US states were warning of methane in water supplies long before the natural gas industry became active in their region.