Is my water meter or prv causing whine, and how do I fix it?
Normally PRV valves take a few seconds to get to the position that is needed to keep the pressure at the set point, I would suggest this is the source of the wine or squeal the water meter if you listen has a little shuttle that goes back and forth the more water that is used the faster it goes back and forth. A PRV has a diaphragm that is spring loaded that controls the actual valve, in some cases the wine or squeal is caused because how far the valve is opened and the fast water flowing through the chambers cause the wine, in other cases at the low flow side a similar thing can happen at a very low flow as far as noise. In the case of low flow it is the valve trying to close and open very slightly this is not normally as loud but the PRV is much more likely to be the cause.