We’ve all heard it before: Drink eight 8-ounce glasses of water each day to stay hydrated and healthy! But the truth of the matter is, there’s no science behind this persistent claim … because every “body” is different. So, how much water should kids drink to stay hydrated, and is it possible to drink too much water? Let’s take a look…

How Does Hydration Work?

While water may be the first thing that comes to mind when thinking about hydration, proper hydration mostly comes down to the concentration of sodium in our blood. 

Sodium is the most important electrolyte¹ in our bodies and comes primarily from salt (sodium chloride or NaCl) in the food we eat. And just as your kid enjoys balancing on one leg, sodium helps balance fluids in and around our cells and tissues, which ultimately determines how hydrated (or dehydrated) we are. 

To better understand how hydration works, consider your sweaty kid after an afternoon of fun at the park. To regulate excess heat while climbing on the jungle gym, her body increases blood flow to the skin, which is then released out into the world… primarily through sweat.

In addition to physical activity, excess body heat can also be caused by too much clothing, or high temperatures and humidity (which varies by person, combination, and circumstance).

Dehydration vs. Overhydration

For most people, drinking the right amount of water isn’t difficult as they drink to quench their thirst even during exercise and in sweltering conditions (a.k.a. a long day at the park in summer). But what happens when you drink too little (or too much) water?


Excessive sweating, diarrhea or vomiting, and a host of other conditions can cause dehydration (also called hypernatremia). This occurs when your body doesn’t have as much water as it needs, but contains too much salt.


Overhydration (also called hyponatremia) is a lesser-known and less common but potentially more dangerous condition that is mostly reported in endurance athletes like marathon runners. Overhydration occurs when your body doesn’t have enough sodium in relation to water. 

If someone drinks too much water too fast, they can get “water intoxication,” which causes an imbalance in sodium and other electrolytes. This imbalance forces water to move from the blood to inside the cells, resulting in swelling that can be serious—especially if it occurs inside the brain. 

Weirdly enough, the signs of overhydration look very similar to those of dehydration:

  • Headache
  • Confusion
  • Diarrhea
  • Nausea
  • Vomiting

Because the symptoms can look so similar, it’s easy for parents to think they need to give their child more water to combat dehydration, but the truth is that the exact opposite is what’s necessary in cases of overhydration.

So How Much Water Should Kids Really Drink Per Day?

While experts recommend that adults use thirst as a guide for when to consume water, the Academy of Nutrition & Dietetics says this alone may not be such a good idea with children

According to Kristi King, a registered dietitian nutritionist and a senior dietitian at Texas Children’s Hospital in Houston, “Children that complain often of thirst may not be drinking enough, because if you experience thirst, you may already be dehydrated.”

In addition to teaching kids to pay attention to when they’re thirsty, parents should also look out for the warning signs. A well-hydrated child is typically energized and has pale yellow urine, but if your child seems sleepier and crankier than usual, or has dark yellow urine, these may be signs of dehydration.

Convincing Kids to Drink Enough Water

Now that we better understand how much water our kids should be drinking to stay hydrated, the next step is convincing them to actually do so – which we ALL know can be a challenge in itself. Fortunately, there ARE ways to make drinking water more enticing for your thirsty little one:

  • Make it a family habit.
  • Keep water easily accessible throughout the day.
  • Make water the only option in your home.
  • Get water from fruits and veggies. 
  • Try adding fruit to your child’s water.
  • Look at your own habits, and try to set a good example for your child.

With this information in mind, you can keep your kids hydrated year-round!

¹Electrolytes are dissolved minerals in blood and other body fluids that carry a positive or negative electric charge and conduct electricity. Particularly important examples include sodium, chloride, and potassium. Maintaining a proper balance of sodium and other electrolytes is vital because they also affect many other bodily processes.