About a week or so ago I started hearing a rumble in the pipes downstairs. It lasts about 10-15 seconds. I've narrowed the noise down to what used to be the laundry room. There are two narrow pipes coming from the wall that feed hot and cold water to an old sink, but they haven't been used in years. About a month ago, construction up the street led to someone shutting off the water without notifying everyone. When I got home I flushed the toilet and there was a loud noise and water sprayed up from the tank. I shut off the tap and went to talk to my neighbours. Long story short, I turned on all the taps in the house to release the pressure, all but the one in the basement, which I forgot about. Then last week the noise started. When I opened the taps downstairs today, there was a little spitting, but not much. I noticed the flow of hot water was stronger than the cold water.

The noise is not constant. Today it happened once in the morning and again after 9pm. It doesn't appear to be connected to regular water usage.

Any ideas?