Hello, recently a very loud howling moaning noise has started in the water pipes. Whenever water is used in any part of the bathroom, the main line into the house begins to vibrate and continues to do so until water pressure returns to a constant stable non-flowing state. I replaced the main ball valve that comes into the house, but no change. There has recently been some plumbing changes done. We had a new line put in from the main, including a meter pit. The water 90's straight up from under the house, then 90's over to a T where the lower T is the take off for the bathroom and hot water supply. After the last 90, and before the T, there is a ball valve, which is the one I mentioned replacing. The pipe coming in is 3/4 copper with a reducer at the last 90 to 1/2 inch before the shutoff ball valve. I've seen a lot in my life, but this is a complete mystery. Any help anyone can offer would be most beneficial. Many thanks. The noise is really really loud!

Place your hand on your meter while someone else turns on a faucet. Do you feel the vibration in the meter?