Being thirsty an/or hungry/ starving are quite similar dream images, as they both illustrate a basic need and stand as main metaphors for one's basic wants, discomfort and insufficiency.
Dreams in which you feel thirst and do not manage to quench it bear a negative significance and symbolize loss, imbalance and lack of fulfillment in your life. If you are thirsty in your dreams, you are obviously eager to 'quench'/ fulfill your wishes and achieve everything you lack - love, caring, attention, protection, sexual intercourse, power, fame and recognition, success in undertakings and enterprises, wealth etc. Moreover, dreaming that you are very thirsty is a metaphor for your lack and urgent need for 'fuel', therefore for energy.
If you eventually succeed in quenching your thirst in such a dream, this bears a positive significance announcing you that you have all the knowledge, skills and resources required to carry out any task, responsibility, activity etc. This is also a good dream omen foretelling that you are going to attain all of your goals.
Quenching your thirst as dream image may also symbolize your hopes, ambitions, aspirations etc.
Thirst in dreams may also be the reflection of your emotional imbalance and inner restlessness. You have to 'quench the thirst inside' - to achieve a general equilibrium in the waking life before you can move forward, towards new and brighter horizons.
Thirst as dream image may also be seen as a symbol for your need to find sincerity and honesty in yourself and in those around you. You do not like to live in lies, doubt, ambiguity and distrust. You need a background clear as water, 'as pure as the lily' to be able to lead your life in peace and tranquility.