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?