Using a powerbomb will cause water in a room to recede until it is gone. Includes an edit to fix the vanilla bug where you keep water momentum if leaving a room with water in it and entering a room without water.

Speed at which water drains from room can be adjusted in patch.

Thanks for assistance from Smiley and Benox50, and Paragon for the stream at https://youtu.be/q9AGUVuCNyE?t=5155 showing code in a tutorial room.