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Maureen Dempsey
Contributing Writer

When Can Babies Drink Water?

Ready to work some H2O into baby’s diet? Here’s the safety scoop on when, why and how.

Can newborns drink water? When it comes to infants, the answer is they shouldn’t. As long as baby’s diet consists exclusively of breast milk or formula, an infant doesn’t need any water to stay healthy and hydrated early on. In fact, a belly full of water might curb baby’s appetite for milk, which could compromise your child’s nutrition. But as they get older it’s important for children to drink water—so when can babies have water to start developing good hydration habits? Here’s the 411 on when to give baby water and how to add H20 to baby’s diet safely.

When Can Babies Drink Water?

You know it’s got to happen sometime—so when can babies have water? Here’s an easy rule to remember: It’s safe to give baby water whenever you start introducing solids, when babies are around 6 months old. They won't take more than a few sips from a cup or bottle at a time—and that’s fine, because they don’t really need it. But letting baby drink water at this stage helps him get used to the taste. "It’s one of the healthiest habits to start early," says California-based pediatrician Tanya Altmann, MD, author of What To Feed Your Baby.

How to get baby to drink water

Once you know when babies can have water, how do you go about giving water to baby? There’s really no right or wrong answer. "Bottle, sippy cup, straw or even tiny sips from a regular cup is fine," Altmann says, noting that bottles may be easiest for infants. "My mom used to use the cap from the bottle as a little cup to pour tiny sips into my boys' mouths. They loved it! They laughed, sometimes spit some back, but got used to the taste of plain water as infants."

How Much Water Can a Baby Have?

From 6 to 12 months, babies don’t actually need water, but a few sips here and there will help them get accustomed to drinking water. Older infants, between 9 and 12 months, can and should drink more—a few ounces a day, Altmann says. Once your child celebrates her first birthday and is eating solids, it’s okay to let baby drink water freely, but only between meals. At mealtime, offer whole milk. (You can start giving baby juice after 6 months of age, but there’s really no nutritional reason to do so.)

Can baby get dehydrated?

As long as baby is feeding well and gaining weight appropriately, he’s unlikely to get dehydrated. The exception is when baby has a cold, flu or other health problem. "When babies are sick they can get easily dehydrated if they aren't drinking enough or if they’re losing fluids through vomiting or diarrhea," Altmann says. How can you tell if baby is dehydrated? Call your pediatrician right away if there are fewer wet and dirty diapers than usual, if baby is lethargic, unusually tired or isn’t making tears, or if the soft spot on top of baby’s head appears sunken. "You may need to breastfeed more frequently, give baby an electrolyte solution such as Pedialyte, or in more serious cases baby may need to be hospitalized for IV fluids," Altmann says.

When is water bad for babies?

While you don’t have to worry about not feeding baby enough water, it is possible to give too much. It happens mainly in an attempt to dilute formula with water, which you should never do as a way to cut calories if you think baby is gaining too much weight too quickly. "When mixing formula, it’s important to follow the instructions precisely," Altmann says. "Too much water can dilute the nutrition and cause serious health problems." In fact, giving too much water can lead to water intoxication in infants, which, while rare, causes babies’ sodium and electrolyte levels to drop, potentially leading to serious medical problems such as brain damage, seizures and even death.

How to Safely Prepare Formula With Water

So is it ever okay to dilute baby formula with water? If you’re not using ready-to-feed formula, it’s fine to mix powdered or condensed formula with either tap or bottled water. "Whether it’s bottled water or tap, what water you use is a personal preference," Altmann says. "Be sure to ask your pediatrician or pediatric dentist if your child needs extra fluoride, depending on what type of water you use and whether or not it contains fluoride." To make sure baby is getting a dose of fluoride, you can mix the formula with bottled water that has added fluoride, or simply give baby sips of bottled water with fluoride. If you use only tap water, note that you may notice slight white spots on your child's teeth, a harmless condition called dental fluorosis. According to the American Dental Association it won’t affect the health of teeth—and may even make teeth more resistant to decay.

"Drinking plain water is one of the healthiest habits you can start with baby," Altmann says. And it makes sense: Infants who drink plain water become toddlers who drink plain water and later kids who drink plain water. "How many adults do you know who don’t like the taste of plain water?” Altmann says. “It’s because they didn’t get used to drinking it as kids."

Just like learning to eat solids, learning to drink water is a process for most babies—and the sooner you start, the stronger this healthy habit will be. So bottoms up!

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