I need some reassurance. I live in a two year old home with two bathrooms upstairs. When the water is drained from the tubs, I can hear the water rushing down the pipe, but I also hear a dripping sound at the same time. I look in the basement where the pipes are exposed, but I don't see any evidence of leaking. It sure sounds like the leak is on the outside of the pipe. Is it possible that you can have a leaking sound and rush of water at the same time or do I have a problem? Both pipes sound the same.