When parents tell me that they think their child is constipated because he or she does not drink enough water, I remind them that diets low in water do not cause functional constipation and that drinking more water is not a treatment for functional constipation. Functional constipation is caused by stool withholding and subsequent rectal distention. I tell them there is no good reason to tell their child to drink more water. Constipated children are no different than other children. They will drink more water when their body tells them to drink more water, that is, when they are thirsty.
In an article in the NY Times titled, "No, You Do Not Have to Drink 8 Glasses of Water a Day" pediatrician Aaron Carroll, an expert in this area, says that, "there is no formal recommendation for a daily amount of water that people need. The amount obviously differs by what people eat, where they live, how big they are and what they are doing."
In my book I point out that the "officially" recommended liquid consumption from all sources for children 1 to 8 years of age is 4 to 5 cups (32 t0 40 fluid ounces). I underlined "from all sources" as a reminder that there are many other sources of water that should be included when trying to determine how much water a child drinks in any given day such as milk, soda, soup, fruit and vegetable juices.