Normally the body loses water through its natural processes such as sweating and urine. A kid needs to have enough water in the body so that they can remain healthy and not suffer from any complications that are associated with lack of water in the body. As a parent you can notice that your kid is suffering from dehydration when they have certain symptoms such as: dry mouth, lack of tears when crying, dark yellow urine in small amounts, and irritability among others.
These are more rampant when the child is suffering from vomiting or diarrhea. To make sure that this does not happen you need to encourage your child to drink lots of water and fruit juices. Ensure that after every meal you have given the child water and at the end of the day they have drunk around 6-8 glasses. If the children are more active and lose a lot of water you should add the intake of the water as they loose more.