why do my water pipes hum, viberate, or bang
As far as the banging, I can help you there.
If the home or building is plumbed properly,there should be vaccume chambers behind all the lavatories. Some times they will get filled with water, so every time you flush a toilet or shut off a valve the pipes will thump or bang.
To correct this you must shut off the main,then take the bonnets off all the stops hot and cold at each lav,holding a small bucket or pan under each. When all chambers have been drained replace the bonnets turn the water on and all should be as normal.
P.S. The bonnett is the nut behind the shut off handle on your lav. stops.
Shut the stop off loosen the nut, when it's loose then turn the handle counter clock wise until the whole stem comes out. To replace just do in reverse.
Thanks Leon The Plumber