I searched but could not find reference to my specific issue. Recently we experienced water hammer at the overhead pipes leading into our 40 gallon gas water heater installed in 2012. Every 4-6 minutes or so the pipes would bang for about 10-15 seconds. Stop and start again fairly consistently. I searched around and figured it couldn't hurt to turn off water to the house and drain the hose outside, as instructed. Sure enough, the water hammer went away. However, I'm curious to know if it's an issue with the pipes in the water heater that will reoccur. What caused it? I've had water hammer before on the old water heater, but that was the usual scenario where you run the hot water and the pipes shudder. That was fixed with a new control valve "nipple" or ball bearing thing. That water heater was replaced due to old age. Thanks.

without knowing for sure what caused the noise, it is impossibe to say if it will come back.