Greg, I fully agree with your recommendation! Unfortunately it doesn't happen all the time and i'm afraid it will turn out just like when i bring my car in for repair, the problem goes away when you are trying to show someone whats wrong. It's the repeatability thing that's confusing me. It doesn't happen all the time, or from a specific location. I need to do more testing to see if its specific to hot or cold water. I've also bought new seats for all of the toilet water valves which i plan to put in this weekend. I would love to just dump this in the contractors lap but i hate to look silly by having him come out and nothing appears to be wrong. I'll also check on some of the other suggestions made to be sure its nothing i've overlooked.