I have a 20 year old house and recently starting having an issue with vibrating water pipes the past couple months. The vibration starts when you shut the water off - usually from a sink or the filling of the toilet. If you turn a faucet back on (any faucet)for a second, it stops the vibration. I've been reading about water hammers and air in the pipes but can't figure out which is more likely.

any suggestions?