My cold water pipes Groan and vibrate. What causes this?

Only the cold? Could be the pressure reducing valve for the house. Next time you hear it, grab the Valve, usually located where water enters house, and see if it is vibrating. Can also be caused by deteriorating globe valve or even a toilet ballcock or float valve.

Brian gave you a bunch of things to check, Here's what a PRV valve looks like, It's located in the basement where the water service enters your house. Good luck and let us know what you find. Tom

Brian gave you a bunch of things to check, Here's what a PRV valve looks like, It's located in the basement where the water service enters your house. Good luck and let us know what you find. Tom

Someday, when I'm older, maybe 72(next year!) I'll learn to post pictures. Thanks, Brian