The fountain is really quiet (is in my living room without nerves!) You have to put together correctly and just stand him only. If the fountain is buzzing louder, it usually suffices to move the cover a Millimeterchen in the one direction or another. That the pump is placed centrally in the well, so they will not hit the housing, probably is also clear!
Because our water is very hard, we use for all devices, including the fountain, a Brita water filter -. Thus, lime no longer an issue.
Among the few negative reviews: If you have two left hands, one should not give the device the blame! The fountain is easy and straightforward to clean and re-assemble (incl. Pump), who thus has problems should watch on YouTube the video or have it show of a friend ... as you can see here on Amazon, there are not sooo many cat owners with 2 left hands ;-)
Tip: Read only the positive reviews because the problems with the fountain is usually due to operator error, apart from the technical defects, but there is for all manufacturers and here they remain well within limits.
Strong buy recommendation and 5 star!
Suggestion: a small bottle cleaner for the hose and nozzle cleaning could be put to, or at least offer ;-)