Water is extremely important for the digestive system. If the body isn't supplied with enough water, it gets the needed amount from internal sources. The colon, for example, is one of the primary sources for water. Water is absorbed by the indigestible fiber of the colon, which increases the bulk of the stool. The lack of the bulk in the colon reduces the urge to eliminate. Too little water in the colon will lead to dry, compact stool and infrequent bowel movements.