I really hope that someone here can help me. After we had our hot water storage tank replaced, we get 1-2 bangs every time we turn off a water faucet, a toilet is finished refilling, or during parts of a washing machine cycle. It's especially bad with the 2nd floor toilet and the washer in the basement. I know that the bangs are coming from the tank area because the bangs disappeared when I shutoff the cold water feed to the tank.

My plumber also confirmed it and believes it to be the check valve, so he added two Watts 150A water hammer arrestors: one on the cold water pipe leading into the tank and one on the hot water pipe coming away from the tank. That hasn't helped. The plumber suggested changing the toilet fill valve to something slower, but what about the sink valves? Finally, he thinks we may have to install a larger arrestor at the main feed to the house, but I'm skeptical that it would work.

Any advice is very much appreciated.