Perhaps, triggerhappy you could provide one such 'well documented' claim? The most recent case, involving a multi-million dollar investigation by the U.S. Government's EPA (Environmental Protection Agency) resulted in the Agency withdrawing any detrimental claims and turning the investigation over to the State of Wyoming (not far from where I live).
Look, fracking takes place at sevral thousand feet below the groundwater bearing rocks in geology... somewhere below 7,000 feet on down to maybe 15,000 feet. The hole drilled for the entry of the fracking pipe is cemented in and sealed.
What can happen is the fracking fluid can be spilled by the operator or other surface related accidents whcih can result in limited surface water damage. But this same sort of possibility is inherent in any oil well drilling process, since the fluids circulated in the hole to clean the drill bit and return geologic samples to the surface must be stored in plastic lined pits until the site is reclaimed.
I realize I seem to be defending the process, but I live here and have been interested in the possibilites since it began. But, differing segments of society have differing bias' and some would like to see a total cessation of fossil fuel production. In my view, that's just not realistic. I'd admit that we need more information... but the information out there right now doesn't do justice to drawing any firm conclusion... in my opinion...