Hi, I just bought a house built in 2005. And I notice there's small water leakage in the interior walls whenever I use the water. In fact, I hear some water drops in the walls. There's a drop in about 3 to 6 seconds. However there's absolutely no damage on the wall, no sign of moisture at all. I was very worried until my parents said that they also have the same problem, and it lasts over 10 years, and they need no repair since there's no damage. Should I be worried about those drops or I shouldn't be too concerned about that ? Thank you very much for your input.