What kind of vibration?
If it is a tick tick tick tick tick, take a look at your water meter. See if the ticking corresponds to the tell tale wheel on the meter.
If it is a whining noise, you could have a bad PRV (pressure reducing valve) or bad rubbers in a frost free shutoff.
If it is a hammering noise like a machine gun, it could be the backflow preventor or the valves themselves.