Seeing someone in trouble, you want to help, just like you want to water the whale, but you are watering the tap water, which means that the water is too small to save the whale, which may symbolize that you are not yourself, and your energy is too small to save the person in trouble.
Interpretation of dreams pays more attention to the emotions in your dreams, and then gives yourself an answer by associating your recent life state and the symbolic meaning of things that appear in your dreams. My answer is just a guess. The true accuracy depends on your own association.