For the last week, my gas water heater has made a loud banging noise once it is done heating the water. It does it no matter how long it runs and it only bangs one time. It sounds the same as when your heating ducts expand/contract when there is any suction present. The water heater is a Whirlpool and it is only 2 years old. Last Fall, the city came out and installed new water and sewage lines so my water was disconnected several times as the connected my line to the new piping and my gas was disconnected twice due to some error on their part. I also had a lengthy power outage this winter as well. I do not hear any other noises from the water heater besides the normal sounds of it running its course. I also have not changed the temperature setting since it was installed so it is still set to the recommended temperature. The flu is connected to the chimney and there is a cover on the outside to keep any debris from blocking the chimney. There has also been no change in the water pressure that I have noticed. I have not flushed out the water heater (I am a new homeowner and was unaware that this should be done regularly so it is on my to-do list) since it was installed. Any help or suggestions that you can offer would be greatly appreciated! I am handy but pretty close to clueless when it comes to the water heater so if you could dumb down your responses so that I have a chance to understand amd answer any clarifying questions you have, it would be wonderful! Thanks in advance!