How much water / fluid does a child need each day?

How much water / fluid does a child need each day?

What it takes to keep your kid hydrated


Water is, or at least should be, the main way kids and teens keep their blood volume–and that keeps their metabolism and kidneys functioning well. In fact, you can usually judge how well hydrated someone is by the color of their urine. (This isn't a potty joke). Clear or light yellow colored urine indicates someone is well hydrated, while dark urine  usually means someone is dehydrated. (Very dark or red urine should prompt a call to your doctor-unless he or she had beets several hours before).

How Much?

All sorts of factors affect how much a child (or an adult) needs. They vary from

  • the child or teen's age and activity 
  • the humidity and temperature outside 
  • and whether the child or teen has health issues.  

As adults, we tend to drink with meals and when we are thirsty–sometimes with fluids like coffee and alcohol which require us to drink even more fluid, because they push more out the kidneys. Even toddlers learn to come to their parents for frequent refills of their cups to lessen their thirst.

But babies need to be fed–and they'll usually take what they need, averaging 16-24 ounces daily as a newborn and up to 32-40 by a year of age. None of that actually needs to be water. The fluid is in the form of breastmilk or formula, carrying all the other nutrients they need as well. Some is also from the food that's eaten. Fruits and vegetables are an excellent source of water (think of watermelon or how juicy a pear or peach can be).  

The amount of fluid we need increases with age.

Age (years)Approximate ounces needed
1 – 340
4 – 844
9 – 13 70 for girls (+10 more for boys)
13 – 1875 for girls (+30 more for boys)

That seems like a lot, but that's because it's not just the 6-8 glasses of water you've been taught that an adult needs. It includes fluids from foods.  And the amounts increase during an illness (particularly with fever, vomiting or diarrhea) and with increased activity and athletics.

water to stay hydrated

What about sports drinks, juices and other beverages?

Sports drinks count as fluids, but the sodium and other minerals they provide are unneeded unless perhaps someone has been sweating in vigorous activity for an hour or more. And the sugars they contain add up as extra calories. Recognize too, that fruit juice has 10 teaspoons of sugar in 12 oz. (the same amount that's in a carbonated soda). So the best choice is my low-calorie, favorite diet drink, water. And if you want flavor, add a lemon, strawberry or cucumber or a few teaspoons of juice.