The palace is ancient. So it makes sense for Celestia and Luna to order a complete overhaul of the waterworks, especially since the old system has been making strange sounds within the walls. All they really wanted was to wash up without dealing with new leaks.
They didn't get it.
They weren't expecting the magical lasers either, but that's plumbing for you.
(Now with author Patreon and Ko-Fi pages.)
Rated C for Crackfic.