My problem is a tapping noise that I notice more in the middle of the night than any other time. It sounds like it is coming from my plumbing pipes in my bathroom. It goes tap, tap, tap, then stops. This goes on all night. It sounds like an animal that is tapping on my pipes. Could this be chipmunks that are tapping around the sprinkler system of my home or could this be possibly a faulty water meter that I hear making this tapping noise? It is driving me crazy. WE have our house on the market and I don't want it to scare potential buyers away. I also hear the tapping noice some during the day, but don't notice it as much as I do during the night.