My wife and I used to live in a house that had a water heater that made banging noises all of the time. It sounded like someone was shooting a shotgun next door! I wanted to explain why this only happens with tank water heaters and how it can happen so quickly.
The banging noise happens to tank water heaters because of sediment that builds up at the bottom of the tank. The dictionary defines sediment as “matter that settles to the bottom of a liquid.” If you google pictures of sediment you will find a lot of pictures that look like rocks. You probably don’t have rocks in the tank of your water heater but you do have flat spots of sediment. When the gas flame turns on underneath the water heater in order to heat it, that is when the sediment will keep the heat from rising properly and will cause the popping sound.
The main cause of sediment build up is because of our water supply. Lubbock’s water is very hard and sediment is already in the water once it is pulled out of the ground. This is another reason sediment build up can happen so fast with a new tank water heater in this area.
Solutions?: To be honest there is not a lot you can do. You could try to flush out the tank but that involves removing the tank and letting all of the water out of it (Not very cost effective). This does not guarantee that all of the sediment will be removed because the drain tube can become clogged with sediment chunks very easily. Also one sediment chunk can still cause a popping sound.
I hope that this helped explain why your tank water heater can make a popping sound. I wish there was more that could be done about this issue and maybe in the future someone will come up with a way to better service this problem or maybe the city will purify its water even more.