I don't think many players have even noticed this bug but as a proud Polish patriot this is an issue that has been bugging me for quite a while.
As of the 41.55 version you can't uninstall a sink, reinstall it (even in the same location as before) and then replumb so that it's connected to the main water source, tried it with a wrench, a piprewrench and any type of pipes in my inventory, simply impossible to do.
Workaround is to move a rainbarrel above it one tile next to it, which will connect the sink to that pool of infinite water and then destroy the barrel (source: tried it myself and confirmation from Beard#0845 on discord).
Not sure what happens once water shuts off tho.
This bug currently remove the possibility of having a reliable water source in the early game in buildings without access to sinks, and generally the ability to move those sinks around.
tldr: We don't have the "plumb" option when moving sinks around and have to do tedious workarounds in order to fix it.