How Much Water Should a 13 Month Old Drink?

A 13-month-old should drink about 4 to 8 ounces (0.5 to 1 cup) of plain water each day, along with their usual breast milk, formula.

You probably hear plenty about staying hydrated — for adults that often means eight glasses a day. But when it comes to a toddler, that rule doesn’t apply at all. Their bodies are smaller, their kidneys handle fluids differently, and a lot of their hydration already comes from milk and food.

So how much water does a 13-month-old actually need? The answer is surprisingly modest: about half a cup to one full cup of plain water daily, plus their usual milk. Here’s what the guidelines say and how to tell if your little one is getting the right amount.

What The Experts Recommend

The CDC recommends that children 12 months and older drink 4 to 8 ounces of plain water per day. That’s the same range the American Academy of Pediatrics (AAP) gives for toddlers between 12 and 24 months — roughly 0.5 to 1 cup.

Water is the best choice for thirst, but it’s not the only fluid. At this age, breast milk, infant formula, or pasteurized whole cow’s milk still provide significant hydration. The AAP recommends whole milk as the primary milk source for toddlers 12-24 months, without added sugars or flavorings.

So if your toddler has a few sips of water with meals and drinks milk throughout the day, they’re likely on track. The water recommendation is a supplement, not a replacement.

Why A Toddler’s Water Needs Are Different

Parents understandably worry about dehydration, but overhydration can also be a concern. A toddler’s kidneys aren’t fully mature, and too much water can dilute sodium levels in the blood — a condition called water intoxication. The brain is the organ most susceptible to this, so behavior changes like confusion or drowsiness may appear.

Here are a few reasons the 4 to 8 ounce range makes sense:

• Small stomach capacity: A toddler’s stomach holds roughly one cup of food or fluid at a time. Too much water can fill them up and crowd out the nutrients in milk and solid food.
• Kidney function: Toddler kidneys are still developing and can’t process large volumes of water quickly. Overloading with water may lead to frequent, watery urination and electrolyte imbalance.
• Milk counts as fluid: A 13-month-old typically drinks 16 to 24 ounces of whole milk per day. That alone provides a substantial portion of their fluid needs.
• Activity and weather change needs: On hot summer days or after active play, a toddler may need slightly more water — but still within the 4 to 8 ounce range. Extra sips throughout the day, not a sudden big cup, are best.
• Water intoxication risk: While rare, drinking too much water too fast can cause hyponatremia. Signs include confusion, drowsiness, and inattentiveness. This is more a risk with forced or excessive water drinking.

In short, water is important, but it’s meant to complement milk and food, not dominate the diet. Let thirst guide you.

How Much Water Should a 13 Month Old Drink Daily?

When people ask about water for a 13-month-old, the answer comes down to the CDC’s 4-8 ounce guideline. But it’s helpful to see how that fits into the bigger picture of toddler nutrition.

For comparison, the AAP notes that between 6 and 12 months, babies also get 4-8 ounces of water per day. From 12 to 24 months, that same water range applies — but cow’s milk becomes a primary beverage. So total fluid intake (including milk) naturally increases.

According to the CDC water recommendation, water is the best drink when a toddler is thirsty. Toddlers need about 2 cups of fluid per day from all drinks combined — about 1 cup from milk and 1 cup from water, give or take.

The table shows how water needs slowly increase with age, but for a 13-month-old the target remains modest. Always remember that the exact amount varies based on activity, weather, and other fluid sources like soups or juicy fruits.

Signs Your Toddler Needs More (Or Less) Water

Reading your toddler’s cues is more reliable than measuring every sip. Here are practical signs to watch for — from the fact doc’s sources — that can help you adjust water intake day by day.

1. Urine color: Very light yellow or almost clear urine suggests good hydration. If it’s dark yellow or orange, your toddler may need a little more fluid. (Be aware that certain foods and vitamins can change color too.)
2. Dry mouth or fewer tears: A dry or sticky mouth, and fewer tears when crying, are early signs of dehydration. Offer small sips of water throughout the day if you notice these.
3. Less frequent urination: If your toddler is peeing less often than usual — fewer than four wet diapers in a day — that’s a red flag. Dehydration can reduce urine output significantly.
4. Excessive thirst: Drinking unusually large amounts (over a gallon per day) may signal a health issue, according to some pediatric sources. If your toddler seems constantly thirsty despite normal intake, check with your pediatrician.
5. Lethargy or confusion: These could be signs of water intoxication or more severe dehydration. A change in behavior — becoming drowsy, inattentive, or confused — warrants medical attention.

Every toddler is different, so use these signs as a general guide. On hot days or when your child is sick, pay extra attention to output and appearance.

Hydration Tips For Hot Days And Illness

When the weather heats up or your toddler has a stomach bug, their fluid needs can shift. The key is to offer small amounts frequently rather than one big cup. According to Boston Children’s Hospital, drinking a few ounces every hour or so, or when thirsty, is a good rhythm.

For mild dehydration — such as after vomiting or diarrhea — the StatPearls clinical guidelines recommend an additional 50 to 100 mL of fluid per episode for children younger than 2 years. That’s about 1.5 to 3.5 ounces extra per episode. The dehydration fluid replacement guide advises using breast milk, formula, or an oral rehydration solution like Pedialyte for these situations, rather than plain water alone, to replace electrolytes.

Always avoid juice, soda, or sweetened drinks. The CDC advises against flavored milks and added sugars for toddlers 12-24 months. If you need to encourage water, try offering a sippy cup with a small amount of water at meals or after outdoor play — never force it.

If symptoms persist or your toddler seems very unwell, contact your pediatrician. Trust your gut — you know your child best.

The Bottom Line

For a healthy 13-month-old, plain water intake should stay around 4 to 8 ounces per day, with whole milk providing most of their daily fluid. Watch for urine color, wet diapers, and overall energy level to gauge hydration. Water needs can rise slightly with heat or illness, but small, frequent sips are better than large amounts.

Your pediatrician knows your child’s growth and health history best — if you’re ever unsure about fluid needs, especially if your toddler has a medical condition or is recovering from illness, a quick call can give you personalized guidance for your little one’s unique situation.