Very nice but I should have investigated or researched this further. Either I didn't see the two items I'm about to discuss or I missed it.

The water is inside a black plastic container, so there is no water in the tank to condense. There is a pressure assist cannister which may need to be replaced at some point, or at least repaired. The instructions are available on YouTube videos.

That being said, I don't find the toilet especially loud if the lid is down. If you have a bathroom with lots of ceramic tile, you may find it noisier just because tile does not absorb sound like drywall.  It flushes very well and thoroughly.