Experts recommend drinking 1600 mL of liquid (~ 54 oz) every 24 hours, requirements that may vary according to a person’s size and activity level. Water is preferred, with other liquids substituted in moderation. Other signs of dehydration may include: headaches, muscle and joint soreness, dark urine, constipation, and kidney stones.
(The Importance of Water. Wilmette, Illinois: The Simon Foundation for Continence, 2014. Print.)