Dreaming of drinking water from the Kausar River symbolizes the acquisition of knowledge, the development of righteous actions, and genuine self-confidence. If you have this dream, it indicates positive changes and improvements in your life. You may experience a new perspective in your thoughts and actions, guiding you along the right path.
From Imam Muhammad Ibn Seerin's Dictionary of Dreams According to Islamic Inner Traditions â entry "Kasha" (page 238).
Kaw1har: (Plenitude; Abundance; A river in paradise.) To drink from the Kawthar river of paradise in a dream means acquiring knowledge, developing correct deeds, having perfect certitude and truly emulating the leading practices and character of God's Messenger, upon whom be peace. Drinking from the Kawthar river in a dream also means repentance from sin, abandoning innovations, marriage to a chaste and a pious woman, replacing unlawful earnings with lawful ones, endowment of leadership and victory. (Also see River)
Note: Islamic dream interpretation depends on the dreamer's circumstances and state. This is a general guide drawn directly from the source book.