Is the discharge of a water-like fluid after waking up from sleep normal, or does it require treatment?

What you are experiencing is a wet dream, which may be from Satan or for another reason. Regarding the wetness, you have the choice to consider it as manī (seminal fluid), in which case you must perform ghusl (ritual bath), or as madhī (prostatic fluid), in which case you must wash what has touched your body and clothes and perform wudūʾ (ablution). This choice is the view of the Shāfiʿī school and is the fatwá (religious ruling) acted upon.