In Pennsylvania, residents are struggling with lack of drinkable well water. People often point to the controversial practice of “fracking” as the culprit, but scientists haven’t found much evidence that gas drilling is to blame — at least not yet.In Pennsylvania, residents are struggling with lack of drinkable well water. People often point to the controversial practice of “fracking” as the culprit, but scientists haven’t found much evidence that gas drilling is to blame — at least not yet.