noise in wall. water leak?

[jaristotle]

When I use the shower or faucet in the bathroom I can hear a noise in the wall/ceiling. It sounds like it could be a water drip...kind of an intermittent metallic clicking noise. The noise tends to become more frequent the longer the water is on, and it's more noticeable when the shower is on. There is no dampness in the wall. Besides a water leak, what are some other possible causes of this noise?

[LazyPup]

While PVC drain piping has a number of advantages, the singular disadvantage is that it is relatively noisy when compared to cast iron waste pipes. In a worst case scenario you can actually hear the water flowing through the pipe, but more often than not, it will sound like a low ticking sound in the wall such as you describe. This is especially true in multistory structures where 3" or 4" stacks run up to the upper floors. You can have some limited success in reducing the sound by physically wrapping the pipe with fiberglass insultion material but in most instances that is not real effective.

In most cases it is not loud enough to be a problem, but rather just one of those little background noises in our homes that normally go unnoticed. The problem is that once someone does notice the sound they begin to think in terms of leaks or expensive plumbing problmes and they tend to tune their ear to the sound. Obviously the level of the sound will be proportional to the amount of water being used at the point of demand, therefore we would often associate the sound to a high demand area such as the shower, while the amount of water being discharged through the same line from a bathroom lavatory would go unnoticed.

In most instances once the sound has been identified and the homeowner has been assured that it is not a pending problem they will no longer notice it in a short time.