Fluid needs vary
A 4-5 year old who takes in 22 ounces of fluid a day, but is otherwise quite healthy, need not be pressured to drink more liquids.
However, if his poop is too firm, or his urine
tends to be medium dark yellow, or dark yellow, then he can benefit from a little more fluid. More fluids can also be helpful during and after exercise
, or on hot days when he will sweat more.