***
Hello... I have a condo that is only 3 yrs old. I hadn't flushed a toilet, taken a shower, or even used a faucet. I was sitting in my living room when a loud pounding happened (coming from the wall and near my hot water heater). This happened twice (about 30 min. apart) but It's never happened before. I've been researching to see what it could be but nothing I found explained my specific situation so here I am. :) I appreciate any feedback. Thanks!

Do you have a gas or electric water heater? Let me know, Tom

Electric

You could install a expansion tank on the cold water feed to absorb the shock. This would also act as a air chamber for the entire system, Good luck, Toim

I'd also check to be sure that the toilet flapper isn't causing the toilet fill valve to turn on periodically... would make the same noise and appear like no water was being used. It is a quick test and just about free, so I recommend that you do the following:

Here, take some food coloring and drip 20 drops into the toilet TANK of each toilet in the home. An hour later, look in the toilet BOWL of each toilet and if you see colored water then the flapper(s) is defective and needs to be replaced... should resolve the noise issue as well... ;)

Otherwise, the expansion tank as Tom mentioned may be needed.

Mark

Thanks for your responses and time!

Have you determined the issue here?