In the United States, about 54.5% of children are not properly hydrated, according to the results of a nationwide study conducted by the Harvard T.H. Chan School of Public Health. 

The research involved school children who underwent urine tests to see whether or not they drink enough water, and the study revealed that they do not. 

"I was surprised that almost one in four kids drank no water during the course of their day," said Department of Social and Behavioral Sciences postdoctoral researcher at Harvard Chan School, Erica Kenney, who led the study.

The researchers also found out that the male students were 76% less hydrated than female students.

"Children don't have a highly developed thirst mechanism, so they're especially vulnerable to becoming dehydrated," said UNC Chapel Hill Gillings School of Global Public Health's Nutrition professor, Dianne Ward. "So parents need to remind their children to drink water," she added.

Proper water consumption for kids according to a specific age group is 4 cups for ages 1 to 3, 5 cups for ages 4 to 8, 7 cups for girls and 8 cups for boys for ages 9 to 13. 

Consuming water that is less than the required amount could lead to mental processing problems, headaches and nausea, according to pediatrician at University of California in San Francisco, Dr. Anisha Patel.

"Keeping kids hydrated can help them with learning and to perform better in school," stated Patel, who has listed water excretion problems such as dry mouth, irregular urination, and inability to cry out as many tears are among the symptoms of mild dehydration.

According to Kidshealth.org, excessive sweating, fever, diarrhea and vomiting are among the common causes of dehydration. To prevent further loss of body liquids, kids should drink plenty of fluids especially when sick or during physical activities.  

Health experts are also advising parents to refrain from regularly providing their children with drinks that have high sugar and caffeine content, which also contribute to dehydration.