Faint dripping sound UNDERNEATH toilet in piping underneath floor
Hello everyone, we live in a 4 years old house and the toilet from the second makes a very faint dripping noise, under the toilet, possibly coming from the floor. There are no leakage from the tank or the toilet. We can clearly hear a dripping sound that coincides with the volume that is put into the toilet bowl. More volume is added, the quicker the dripping noise goes and then slows down a few moments after the entire flushing cycle is over. The noise is NOT a noise of water flowing down the drain as fluid is added to the water contained in the toilet. The sound is a DRIPPING noise, coming from a pipe within the floor, underneath the toilet. I am no plumber but this is the best way to explain it.
This toilet is on the second floor, and I don't notice any odor or wet spots on the ceiling from the first floor, but I wonder if there might be a leak causing the dripping noise? Is it possible the water is dripping internally to the pipe and causing the noise, or should I be concerned for a much bigger problem and water dripping inside the wall or in the floor? I find it hard to believe a drip could exist within a pipe since fluids prefer to travel along the surfaces of objects.
Please & thank you!