I can hear water dripping drop by drop but cannot determine the cause of this problem. I replaced a new valve and still having this problem. This is happening with two toilets in the house. Any suggestions? Could this be sealer problem? One toilet with the new valve, once every 15min, it makes this sound like you are flushing the toilet. What I noticed during this time, there is water flowing out from the overflow tube in the overflow pipe. Why does it do this? What do I need to replace to solve this issue?