Noisy Water

Does the water flow seem to be steady or does it spurt or change pressure? If you turn off the city supply and use the pump & potable water tank, do you still get the noise? Can you tell where the sound comes from, or does it seem to be all through the water lines? Does the sound change when you run hot water?

At this point, I don't think of suggestion not already given, but perhaps some details about the sound might point someone here in the right direction.