Since I replaced the innards of the guest bathroom toilet, our pipes have started singing to us, a high pitched wail of sorts, when we use any plumbing on that side of the house. Both toilets, the sinks in both bathrooms, the tubs, and the shower all cause this noise, both hot and cold water. The kitchen sink and the laundry room on the other side of the house don't seem to be involved. The noise is loudest near the master water valve in the garage next to the water heater, both of which are on the "non-involved" side of the house. Our plumbing is about 7 1/2 years old, and we've never had this problem before. Any thoughts? Thank you.