Over the past year or poss longer have been hearing loud humming in bsmt water pipe. It does move around some and the pipe does vibrate when it hums. It is now almost continuous and lasts sometimes much longer than a few seconds. House was built in 1992.very large house -5600 sq ft-3 half baths, 4 full;sprinkler system.should I call in someone?have tried opening taps-but there are so many-didn't do them all at once.

Just wanted to add that the humming sounds like a loud foghorn

No need to start a new thread each time. You can edit your old post or add to it in the answer box, we'll try to merge these. Does the hum coinicde with any fixture use like flushing a toilet or using the sprinkler? Sounds like a vibrating seal like in a ball cock.

Sounds like there is a valve that may not be open all the way some times that creates a vibration when water passes through