Is Your School-Age Child Drinking Enough Water?

As parents, we spend a lot of time thinking about what our children are eating, but how much attention do we pay to what (and how much) they’re drinking?

Hydration is foundational to nearly every system in the body, yet it’s one of the most overlooked aspects of children’s health. Research shows that nearly 1 in 2 school-age children in the U.S. are not adequately hydrated (1), and mild dehydration can affect mood, learning, digestion, and immunity (2,3). For some kids, this may be happening before a child feels “thirsty.”

In this article, you’ll learn about the signs of dehydration and how much water your child should be drinking each day, plus several practical tips to help keep your child hydrated.

Some of the most important reasons hydration matters for school-age kids include:

The brain is about 75% water. Dehydration can negatively affect:

• Short-term memory,
• Attention span,
• Vigor (4).

In one study, children who drank water before cognitive testing scored significantly better than those who did not (5). This means something as simple as having a water bottle on hand may directly support academic success.

Chronic constipation is one of the top pediatric complaints, and inadequate hydration can be a contributing factor (6). Without enough water:

• The colon reabsorbs too much fluid from stool, making it hard and difficult to pass;
• Bowel movements become less frequent, which can cause pain, bloating, and behavioral issues;
• Toxin elimination slows down, contributing to gut dysbiosis, irritability, and sluggishness.

For children who already struggle with picky eating or low fiber intake, water becomes even more essential to keep things moving.

To learn more about constipation in children, read this article: Treating Constipation In Kids & Babies With Integrative Medicine.

Water is a detoxifier by nature (7). It helps the body:

• Filter waste through the kidneys
• Eliminate toxins through urine, sweat, and the lymphatic system
• Maintain healthy mucosal barriers in the respiratory tract and digestive system

Children are regularly exposed to environmental toxins, food additives, and germs, so supporting the body’s natural cleansing processes matters!

To learn more about detoxification in kids, read these articles: 

• What Is Detoxification?
• 10 Ways To Support Detoxification In Kids

Hydration needs vary based on age, activity level, body size, diet, and climate. Here are some general guidelines for kids (8,9). The amounts listed below are a good "base" to work from, but please know that certain conditions will further increase your child's fluid intake needs.

These totals include fluid from food (soups, fruits, veggies), but plain water should still make up the majority.

There are situations when your child may need additional fluids beyond the above intake guidelines. These situations may include:

• Hot weather or living in dry climates
• Sport practices, especially outdoors
• Fever, vomiting, or diarrhea
• High intake of salty, processed, or high-protein foods
• Kids who don’t eat many fruits or veggies (which provide water)
• Kids taking fiber supplements or who are constipated

To learn more about dehydration, read this article: Signs of Dehydration In Kids & Infants. Plus Dr. Green Mom’s Homemade Electrolyte Drink Recipe

It’s important to note that babies under 6 months should never be given plain water, as their kidneys aren’t mature enough to handle it. Even small amounts can dilute sodium levels and lead to a dangerous condition called water intoxication. After 6 months, small sips of water can be introduced alongside solids, but breast milk or formula should remain their primary source of hydration for the first year.

When it comes to school-age children, overhydration is still a possibility, though it is not common. It’s more likely to happen when:

• A child is pressured to drink excessive amounts of water, especially without adequate electrolytes.
• A child consumes very large amounts of plain water after intense sports or sweating, without replenishing sodium and potassium.

This can result in hyponatremia, a condition where electrolyte levels become dangerously diluted, leading to confusion, nausea, headaches, or more serious complications if not addressed.

To avoid overhydration in school-age children:

• After long sports sessions or heavy sweating, offer electrolyte-rich options like coconut water, sea salt with lemon in water, or (homemade) electrolyte drinks;
• Add mineral drops to filtered water if your water source is very soft or demineralized.

Children don’t always recognize thirst, or they may ignore it to continue with their preferred activity! Some potential signs of dehydration in kids include:

• Headaches
• Fatigue or irritability
• Dry lips or cracked skin
• Constipation or infrequent stools
• Dark yellow or strong-smelling urine
• Difficulty concentrating
• Dizziness, especially during sports or hot days
• Bad breath (can signal dry mouth)

It’s common for kids to forget to hydrate during the school day. Some of the most common reasons include:

• Classroom rules that don’t allow water bottles at desks,
• Reluctance to ask for bathroom breaks during lessons,
• Distraction during playtime, when drinking water is the last thing on a child’s mind.

It can be tricky to keep your child well-hydrated during the school day, especially when you’re not there to remind them. Here are some simple ways to help set your child up for success:

• Send a refillable bottle your child loves that they can open/close independently.
• Freeze the bottle part-way full overnight so it stays cold (if your child prefers cold water).
• Pack hydrating foods like cucumbers, citrus, berries, and bell peppers.
• Remind your child to drink during transitions: before recess, after PE, before lunch.

If your child does not feel motivated to drink plain water, get creative! Here are some ideas:

• Let kids add fruit slices, herbs, or chia seeds to their water.
• Serve herbal teas or herbal tea Arnold Palmers (herbal tea mixed with lemonade!).
• Make homemade popsicles.
• Use silly straws or cups to make drinking fun.
• Model hydration yourself! Kids mirror our habits!

Half of school-age children in the U.S. aren’t drinking enough, and even mild dehydration can impact their mood, focus, digestion, and immunity. Encourage adequate hydration by choosing fun water bottles, cups, or straws; adding fruit; or preparing herbal teas or homemade electrolyte drinks. Hydration for infants less than 12 months old should come from breast milk or formula.

1. Shaheen NA, Alqahtani AA, Assiri H, Alkhodair R, Hussein MA. Public knowledge of dehydration and fluid intake practices: variation by participants' characteristics. BMC Public Health. 2018 Dec 5;18(1):1346. doi: 10.1186/s12889-018-6252-5. PMID: 30518346; PMCID: PMC6282244.
2. Popkin BM, D'Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58. doi: 10.1111/j.1753-4887.2010.00304.x. PMID: 20646222; PMCID: PMC2908954.
3. Penkman MA, Field CJ, Sellar CM, Harber VJ, Bell GJ. Effect of hydration status on high-intensity rowing performance and immune function. Int J Sports Physiol Perform. 2008 Dec;3(4):531-46. doi: 10.1123/ijspp.3.4.531. PMID: 19223676. 
4. Zhang N, Du SM, Zhang JF, Ma GS. Effects of Dehydration and Rehydration on Cognitive Performance and Mood among Male College Students in Cangzhou, China: A Self-Controlled Trial. Int J Environ Res Public Health. 2019 May 29;16(11):1891. doi: 10.3390/ijerph16111891. PMID: 31146326; PMCID: PMC6603652.
5. Edmonds, C. J., & Jeffes, B. (2009). Does having a drink help you think? 6–7-Year-old children show improvements in cognitive performance from baseline to test after having a drink of water. Appetite, 53(3), 469–472.  https://doi.org/10.1016/j.appet.2009.10.002
6. Boilesen SN, Tahan S, Dias FC, Melli LCFL, de Morais MB. Water and fluid intake in the prevention and treatment of functional constipation in children and adolescents: is there evidence? J Pediatr (Rio J). 2017 Jul-Aug;93(4):320-327. doi: 10.1016/j.jped.2017.01.005. Epub 2017 Apr 25. PMID: 28450053. 
7. Rani, J., Sharma, U. K., & Sharma, D. N. (2018). Role of adequate water intake in purification of body. Environment Conservation Journal, 19(1&2), 183–186.  https://doi.org/10.36953/ecj.2018.191226
8. Rethy, J. (2020, January 27). Choose Water for Healthy Hydration. HealthyChildren.org.  https://www.healthychildren.org/English/healthy-living/nutrition/Pages/Choose-Water-for-Healthy-Hydration.aspx
9. Wein, H. (2023, April 25). Hydrating for Health. NIH News in Health.  https://newsinhealth.nih.gov/2023/05/hydrating-health