I have heard a noise for the past month in my water lines, in the wall where the main water shut-off is located. However, it is not constant. It is a humming/gurgling noise in my lines. Im thinking that it originates from my main water shutoff point, because when you put your hand on the valve, you can feel the vibration. Sometimes it makes noise, sometimes it does not, sometimes quietly, sometimes very loud. Its very sporadic. When the main water shut off is turned off, the noise goes away. I'm thinking (and hoping) its not a leak. I live in a condo with a cement slab, and after four weeks of this, I'm pretty sure I would have seen some water by now, if it was a leak. I really feel that the problem is in the main water line, and not the other lines running through the house.
Any ideas? Thank you.