some companies are starting to take preemptive actions, presumably to protect themselves, against claims of groundwater contamination in reservoirs being hydro-fracked. For example, these companies are doing baseline groundwater measurements prior to doing stimulations. I know of one case where the company didn't log the well or take core or fluid samples in the reservoir rock, however, they took water samples from an aquifer several thousand feet above the reservoir and several thousand feet below the surface (that doesn't mean they won't do logs or reservoir sampling later). Of course, these measurements are only really meaningful in relatively virgin areas of a reservoir (e.g. a couple of miles away from existing wells; however, that distance will depend on things like when neighboring wells were drilled and flow rates).
One of the most severe criticisms of the PNAS paper that insinuated fracking operations had contaminated groundwater in PA was that it had not used or carried out any baseline groundwater measurements.
