Take the 2-minute tour ×  Earlier today, I noticed a strange,
repetitive clunking noise from the vicinity of my water heater.
After some investigation, it seems to come from the cold water
supply to the water heater.  Here's what I've found:    •
turning on a faucet quiets the noise temporarily. After shutting
off the faucet, it stays quiet for a bit, then the noise comes
back.   • turning off the cold water supply to the heater stops
the noise (and the water)   • the noise occurs while no water is
being used in the house.   • the noise repeatedly clunks about
once a second.  Any ideas what this might be? Is it something
that needs fixing, or can it be safely ignored?  share|improve
this question maybe something that involves overpressure? – 
Asaf Chertkoff Apr 5 '11 at 4:54 add comment  2 Answers  up vote
6 down vote accepted  I had this exact scenario in my home and
the culprit turned out to be a failing pressure regulator valve.
It's typically installed after the shutoff valve where the line
enters the hom