The Complete Guide to Interpreting Your Dreams

by Stearn Robinson - Tom Corbett
The message contained in this dream relates to the amount of water contained in the reservoir.

If it was full up, it predicts full prosperity; if it was empty, it portends difficulties though not of your own making.

Partially full suggests sufficient resources for your requirements, and if the reservoir was in the process of filling, the wind of change will soon be blowing some new opportunities your way.

A Dictionary of Dream Symbols

by Eric Ackroyd
(1) A reservoir may symbolize either your unconscious or your potential - all the unrealized, because not yet chosen, possibilities for your personal development.

(2) Running water may symbolize emotion; so, a calm stretch of still water may represent an untroubled state of tranquillity, or the emotionally virginal state of a (young) person whose emotions have not yet been roused.

Complete Dictionary of Dreams

by Dr. Mıchael Lennox
Any water in a dream is symbolic of the emotional side of your nature. In the case of a reservoir, there is the element of storage of the sustenance of life that is represented by this humanmade structure. When a reservoir features in your dream, you are remembering the importance of emotional expression as a natural part of your functioning humanity.