re: Vibrating water heater

The easiest fix for this kind of knocking is to first turn off your main supply valve. Make sure you communicate to anyone in your home that you are shutting off the valve as it will stop ALL water coming in. Now, flush the lines by opening all of the faucets and flushing your toilets. Water can still leave your home through drainage pipes and this will ensure all of the supply lines are fully empty.

Once the lines are cleared, feel free to turn your main valve back on. It is important to do this slowly so that the air chambers between and around your pipes have time to refill before the water courses back into them. However, now that the pipes were fully emptied, the knocking sound should be completely gone.