See this summary of a study done by University of Texas at Austin presented at the AAAS conference that finds ‘no’ link to hydraulic fracturing and water contamination:
But let me focus one admittance in this article:
The study, released at the annual meeting of the American Association for the Advancement of Science (AAAS) in Vancouver, British Columbia, found that many problems ascribed to hydraulic fracturing are related to processes common to all oil and gas drilling operations, such as casing failures or poor cement jobs.
University researchers also concluded that many reports of contamination can be traced to above-ground spills or other mishandling of wastewater produced from shale gas drilling, rather than from hydraulic fracturing per se, said Charles “Chip” Groat, an Energy Institute associate director who led the project.
“These problems are not unique to hydraulic fracturing,” he said.
So, in other words, water contamination has occurred, but because the contamination was due to equipment breakdown – faulty casing – or mishandling of material on the surface, it is not due to hydraulic fracturing itself. Which means necessary activity connected to hydraulic fracturing caused, or at least facilitated, water contamination… but hydraulic fracturing did not. Huh.