we are having some interior drain tile put in, which requires a lot of jackhammering of the floor, around the perimeter of our basement. the second day they were at it, we noticed that we had brown, cloudy water in our toilets and coming from our sinks. we flushed all of the fixtures, and it eventually cleared up. now, a few days later, this has happened again. i know they came quite close to our main water line as they were jackhammering, but they told us they did not hit anything. they also do not seem too concerned about the murky water. we've had no problems like this is the past. our house is about 50 years old (so it's likely we have iron pipes), and we have city water. i'm pretty sure they're not flushing our hydrants or anything. is it possible they just knocked something loose? how can we tell if it is a more serious problem? does it seem likely this is going to be a permanent issue? should i ask the contractor to call a plumber, or is this our problem at this point? i feel like it needs to be resolved now, before they re-pour any concrete...