Originally Posted by Marlin
It would be a strange leak to be letting air in. I'd ask the neighbors if they're having similar problems or call the water district and ask if they're doing work on the lines.
I had a leak three years ago that was doing just that. I'll post some pictures when I get home of the crusty buildup from calcium. It was leaking verrrrryyyyy sloooowwwwllllyy, but when the kitchen faucet was opened, it provided enough suction to let in some air. Not a ton....it wasn't spitting and popping like it was drained or anything...but a little gurgling and bubbles in the stream.