Many parents ask when can babies drink water, and timing is important. Giving water too early can reduce breast milk or formula intake and, in rare cases, increase the risk of water intoxication. Pediatric experts recommend no water before 6 months, small sips with solids from 6–12 months, and water becoming a main drink after 12 months. This guide explains the age-based rules, safe amounts, and practical tips for introducing water safely.
Key Answer: When Can Babies Start Drinking Water? (By Age)
If you’re wondering when babies can drink water, here’s the clear timeline most pediatric guidance follows.
0–6 months: no water (breast milk/formula only)
For babies under 6 months of age, don’t give your baby water. This includes “just a few sips,” water from a bottle, and water between feeds. At this age, breastfed babies and formula-fed babies get all the hydration they need from breast milk or formula. According to the World Health Organization (WHO), breast milk is about 85% water, providing all the hydration a young baby requires. Even if it’s hot outside, young babies don’t need water. They need more frequent milk feed instead.
6–12 months: small sips with meals (skills + hydration)
At about 6 months of age, many babies start solids. That’s also when most guidance says you can start offering your baby water in small amounts, mainly for practicing cup skills and supporting meals.
A typical total range is 2–8 ounces of water per day, offered as small sips of water with solid foods. The key point is that breast milk or formula still does heavy lifting for hydration and nutrition. Water is necessary, but it’s "in addition" to the main feeds, not a replacement.
If your baby is 6 months old and you’re eager to offer water, think “a few sips,” not “a full cup.”
12+ months: water becomes a primary drink
After 12 months, many toddlers can have water available throughout the day and use it as their main thirst-quencher. Milk can still be part of the diet, but water becomes a primary drink. Babies and water have a new relationship, as toddlers rely more on water for hydration and less on milk as they grow.
A common range for toddlers is 8–32 ounces of water per day, depending on age, foods, weather, and activity. Some days your child will drink more, some days less. That’s normal.
Daily water needs by age (limits & priorities)
This table keeps things simple: age, a practical daily range, the best way to offer water, and what to watch out for. (These are general ranges for healthy children. Always follow your clinician’s guidance if your child has medical needs.)
| Age | Typical safe water range | Best method | Priority & cautions |
| 0–6 months | 0 oz/day | None | Breast milk or formula only. Water can displace calories and may raise water intoxication risk. |
| 6–12 months | 2–8 oz/day total | Water from a cup (open or straw; sippy if needed) with meals | Milk/formula stays primary. Offer sips with solids; avoid “water breaks” that reduce feeds. |
| 12–24 months | 8–32 oz/day | Open cup or straw cup through the day | Water becomes main drink. Keep milk reasonable so it doesn’t crowd out iron-rich foods. |
Why no water before 6 months (science + safety)
It can feel strange to hear “no water” because adults reach for water all day. So why is offering water 6 months a problem?
Infant kidney maturity & electrolyte balance (hyponatremia risk)
Young babies’ kidneys are still maturing. They are not as good at handling extra water and keeping the right balance of salts (electrolytes) in the blood. When a baby consumes too much water, it can dilute sodium levels. Low sodium is called hyponatremia, and in babies, it can lead to water intoxication. The CDC warns that in extreme cases, this can result in seizures.
To put it simply: too much water in a small body can throw off the body’s chemistry. Severe cases are uncommon but serious, which is why Healthy Children advises avoiding water entirely before 6 months unless a medical professional tells you otherwise.
“Fills the belly” – how water displaces calories & slows weight gain
Another issue is that water has no calories. A tiny stomach can only hold so much. If a baby drinks water, they may feel full and drink less breast milk or formula. And milk feeds are not just liquid; they are the main source of calories, protein, fats, vitamins, and minerals in early life. If water replaces milk, weight gain can slow, and babies may not get the nutrients they need. The WHO states that feeding water instead of breast milk or formula can negatively affect a baby’s growth.
Hot weather myth-busting: hydration without water
Hot days make parents nervous, especially if a baby feels warm or sweats a little in the car seat. You might think, “Should I give water to prevent dehydration?” For babies under six months, the safer answer is usually: offer feeds more often.
If you’re breastfeeding, you may notice your baby wants to nurse more frequently. If you use formula, you might offer smaller, more frequent feeds. That’s how young babies increase hydration.
If you suspect heat illness (very hot skin, unusual tiredness, poor feeding, fewer wet diapers), call your pediatric clinician right away. But routine “extra water for heat” is not recommended for infants under 6 months.
Red flags: signs of overhydration (seek urgent care)
If you ever suspect your baby has had too much water or diluted formula, do not wait and see. Seek urgent medical care if you notice:
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Unusual sleepiness or hard to wake
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Vomiting
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Puffiness or swelling (especially face)
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Muscle cramps or unusual jitters
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Seizures
These symptoms can have other causes too, but they should always be treated as urgent in a baby.
How Much Water Should Babies Drink? Daily Water Amounts by Age
Once you reach the age when babies can start drinking water, the next question is almost always: “Okay, but how much water is safe?”
6–12 months serving strategy: sips at meals, not bottles
The CDC recommends offering water only with meals and snacks when solids are introduced, while still keeping milk feeds as the priority. A practical approach is to offer 2–8 ounces of water per day, mainly during mealtimes.
12+ months: water becomes the primary drink
For toddlers over 12 months, Healthy Children advises that water should become the main drink for thirst, with milk still being a part of their diet. On average, toddlers should consume 8–32 ounces of water per day, depending on age, weather, and physical activity.
Upper limits & common mistakes (dilution, frequent water breaks)
Two mistakes cause most problems:
The first is adding extra water to formula. Never do this. Powdered formula with water must be mixed exactly as the label says. Adding extra water can lower calories and disrupt electrolytes. If formula is expensive or supplies are tight, reach out to a local health department, community clinic, or social services for support—don’t stretch formula with water.
The second mistake is making water a habit of feeding a baby under 12 months. If you notice that drinking water leads to smaller bottles or shorter nursing sessions, scale back water and return to offering it only with solids.
Do / Don’t (quick checklist):
| Do | Don’t |
| Offer small sips of water from a cup with meals after 6 months | Give water in a bottle to a young baby |
| Keep breast milk or formula as the main drink under 12 months | Use water to “hold baby over” between feeds |
| Mix formula exactly as directed | Dilute formula or add extra water |
12–24 months range: balancing water, milk, and solids
After 12 months, water can be the main drink for thirst. Milk becomes more of a food (nutrition) than a hydration tool. Many toddlers do well with water offered throughout the day, plus milk at meals or snack times if it fits your plan.
A common toddler range is 8–32 ounces of water per day. That’s a wide range on purpose. A toddler eating soups, fruit, and other water-rich foods may drink less. A toddler running around outside in warm weather may drink more.
If you find your child is drinking huge volumes of water and seems constantly thirsty, bring it up with your clinician. Constant thirst can sometimes signal a medical issue.
Dehydration vs normal variation: what diapers and urine color suggest
Parents often ask, “How do I know my baby is getting enough water?” For babies under 12 months, the main question is really, “Is my baby getting enough milk?”
Still, diaper checks help. While every baby differs, many infants will have several wet diapers a day. Urine that is pale yellow is usually a good sign. Very dark urine, very strong smell, dry lips, or fewer wet diapers than usual can suggest dehydration, especially if paired with poor feeding or sleepiness.
Here are simple cues that many caregivers use:
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Several wet diapers throughout the day are reassuring.
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Pale yellow urine often suggests good hydration.
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Dark yellow urine plus low energy or poor feeding is a reason to call your clinician.
If you want a simple “tracker,” you can make a quick note on your phone: feeds, wet diapers, and your baby’s energy level. Patterns are more helpful than at one moment.
How to Safely Introduce Water to Babies at 6 Months (Step-by-Step Guide)
So, when can you introduce water to babies in a way that feels calm and safe? For most families, the smoothest start is tied to solids.
Step-by-step: a simple first week
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Start at a meal with solids (often lunch). Offer milk first so your baby isn’t too hungry.
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Put 1–2 ounces of water into a small cup (open cup or straw cup).
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Offer a few sips after a few bites of food. Pause and watch your baby’s cues.
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Stop when your baby turns away, coughs, or seems done. The goal is practice, not volume.
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Repeat once a day at first. Add another meal later if it’s going well.
If your baby takes only one sip and then plays with the cup, that’s still progress. Learning to drink is a skill.
Best Cups for Babies: When Can Babies Start Using Cups for Water?
Cup choice matters more than many parents expect, because it affects how fast water flows and how much a baby can gulp.
An open cup (with help) teaches careful sipping and can slow things down. A straw cup can be great for skill-building and is often less messy once learned. A sippy cup can be useful, but some designs let toddlers sip for long periods, which can become a constant habit. If you use a sippy, it helps to treat it like a “meal-time cup,” not something carried all day.
If you’re unsure, start with a straw cup or small open cup and see what your baby handles best.
Best times to offer water (pairing with solids)
The easiest rule to remember is: milk first, water with food.
Offer water after a few bites of solids. This helps rinse the mouth and supports swallowing textures. It also protects milk intake because your baby has already had the main drink.
If your baby has reflux or spits up easily, slower, smaller sips are often better than big gulps.
Water-rich foods as an alternative hydration boost
If your baby isn’t interested in water at first, that can be okay. Many foods add hydration naturally once solids begin. Depending on your baby’s age and texture skills, water-rich options can include soft fruit, cooked vegetables, and soups with appropriate ingredients.
A few examples many families use after solids are established include cucumber sticks (prepared safely), watermelon, oranges (membrane removed if needed), yogurt, and brothy foods. These are not a replacement for milk feeds under 12 months, but they can support hydration as your baby’s diet expands.
Troubleshooting: baby refuses water or coughs with sipping
Refusing water is common. Some babies act offended by plain water at first because breast milk or formula is sweet and familiar. If your baby refuses, wait a few days and try again. Keep it low-pressure.
If your baby coughs, it may be a fast flow, a tricky cup, or posture. Try a slower cup, offer smaller sips, and keep your baby upright and supported. If coughing happens often with liquids, mention it to your clinician so they can check swallowing safety.
Water quality, fluoride, and preparation (parent concerns)
Once families hear “Okay, water is allowed after 6 months,” the next question is often, “What type of water is best for babies?”
Tap vs filtered vs bottled: what matters most for infants
For most families, safe tap water works well, especially if your local water system is monitored. The biggest concern in many places is not the water itself, but old plumbing that can add lead. If you live in an older home or you’re not sure about your pipes, it’s smart to look up your local water report and ask about lead testing.
Filtered water can reduce some contaminants, depending on the filter type. Bottled water varies a lot, and it’s not always “cleaner” than tap. The most important thing is that the water is safe, clean, and appropriate for mixing formula if you use it.
If your area has a boil-water advisory, follow it. If you’re traveling to a place with uncertain water safety, use sealed safe water or boil water as recommended.
Is RO water OK for babies, and do you need to boil it?
Many parents ask whether Reverse Osmosis (RO) water is safe for babies. The EPA confirms that RO water is generally safe for babies over 6 months, as long as the water comes from a clean, treated source and the system is maintained properly. However, RO water can remove beneficial minerals like fluoride, which can be important for dental health. It’s a good idea to talk with your pediatrician or dentist if you mainly use RO water for your baby’s hydration.
Do we need to boil RO water for babies?
Do we need to boil RO water for babies? Boiling is about killing germs, not removing chemicals. If your RO water comes from a safe, treated supply and your system is well maintained, boiling is often not necessary. But if your water safety is uncertain, if you’re using well water, if you’re traveling, or if there is a local advisory, boiling (then cooling) can be a safer choice.
Also remember: boiling does not remove lead. If lead is a concern, testing and proper filtration are the right steps.
Fluoride questions (especially for formula-fed babies)
Fluoride helps prevent tooth decay. Some community water supplies contain fluoride, and some do not. If you use a lot of formula, fluoride exposure may be higher if your tap water is fluoridated. If you use RO or distilled water most of the time, fluoride exposure may be lower.
There isn’t one perfect answer for every child. The practical step is to check your local water fluoride level and discuss it with your child’s clinician or dentist, especially once teeth appear.
Special situations: when advice may differ
Most healthy babies follow the 0–6 / 6–12 / 12+ rule. Still, there are times when your clinician may tailor the plan.
Premature babies or medical conditions (kidney/heart issues)
If your baby was born early, has kidney problems, heart issues, or takes certain medications, fluid rules can change. In those cases, don’t rely on general guidance from the internet. Ask your neonatologist or pediatric clinician exactly how to handle water intake and feeds.
Illness (fever, vomiting, diarrhea): water vs ORS guidance
When babies are sick, parents often want to “push fluids.” That’s a good instinct, but the type of fluid matters.
For vomiting or diarrhea, plain water alone may not replace needed salts. Many clinicians recommend an oral rehydration solution (ORS) for dehydration risk, used in small frequent amounts, and they may advise continuing breast milk or formula. The right plan depends on age and symptoms.
If your baby is under 6 months and has vomiting, diarrhea, fever, or fewer wet diapers, contact a clinician promptly before giving water. For older babies, ask whether ORS is appropriate and how much.
Very hot climates & high activity (older infants/toddlers)
For babies under 12 months, milk/formula remains the priority even in heat. After 12 months, you can offer water more freely. A simple approach for toddlers is to offer water at transitions: after waking, with meals and snacks, after outdoor play, and before bed (if it doesn’t disrupt sleep).
If heat is intense, focus on shade, cool clothing, and avoiding the hottest part of the day, not just more drinking.
Daycare and caregiver scripts (prevent well-meaning mistakes)
Sometimes the biggest risk is a helpful caregiver who thinks babies “need water.” A short script can prevent confusion. Here’s a copy/paste note you can send:
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“Please do not give any water because my baby is under 6 months. Milk feeds only.”
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“Now that my baby is 6+ months, water is okay only as small sips with meals in a cup. Please don’t replace milk feeds with water.”
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“Never dilute formula with extra water.”
Keeping it simple makes it easier for others to follow.
What to avoid: unsafe drinks and common myths
Once water enters the picture, other drinks often sneak in. Some are best avoided.
No juice under 12 months (and why)
Juice can seem harmless, but it adds sugar without the fiber you get from whole fruit. It can also reduce appetite for nutrient-rich foods. Many pediatric groups advise no juice under 12 months. After that, if juice is used at all, it’s usually limited and offered in a cup, not a bottle.
Cow’s milk timing and limits (post-12 months)
Cow’s milk is generally introduced after 12 months for many children. Before that, it can interfere with iron intake and does not match infant nutrition needs the way breast milk or formula does.
After 12 months, milk can be part of meals, but water should often be the default drink for thirst. Too much milk can crowd out iron-rich foods, which some toddlers already struggle to eat.
Herbal teas, electrolyte drinks, and “flavored waters”
Herbal teas are not automatically safe for infants, and some herbs can affect the body like medicine. Electrolyte drinks and flavored waters can bring extra sugar or sodium that babies don’t need. For most healthy babies, the drink plan is simple: breast milk/formula first, then plain water in age-appropriate amounts, then regular family beverages only as advised by your clinician.
Myth-busting roundup (quick hits)
Many parents hear these lines from relatives or social media:
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“Babies need water in the heat.” For young infants, more milk feed is usually safer than water.
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“Constipation needs water at 3 months.” Under 6 months, talk to a clinician instead of adding water. At 6+ months, food changes often help more than water alone.
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“Diluting formula is safe.” It isn’t. It can lower nutrients and raise water intoxication risk.
Wrap-up: actionable takeaways (summary)
If you only remember one thing about when babies can drink water, remember the three-stage rule.
For 0–6 months, babies don’t need water and should not have it. They get the water they need from breast milk or formula.
For 6–12 months, babies can drink water in small sips from a cup with meals, usually 2–8 ounces of water a day total, while milk stays the main drink.
For 12+ months, water becomes the main drink for thirst, often 8–32 ounces a day, adjusted to the child.
If you want a “one-screen recap” for your fridge, write: 0–6: none. 6–12: sips with solids. 12+: water as the main drink.
Short FAQs
1. Can babies drink water at 4 months?
No, babies under 6 months should not be given water. At this age, breast milk or formula provides all the hydration they need. Giving water can actually interfere with their intake of breast milk or formula, which could lead to slower weight gain. If you're worried about your baby being thirsty or dehydrated, offer more milk instead. If you notice fewer wet diapers, unusual tiredness, or other signs of dehydration, it’s best to contact your pediatrician for advice.
2. Can babies drink water at 6 months?
Yes, around 6 months is when most pediatricians say it’s okay to introduce water, but it should only be in very small amounts. Think of it as “small sips,” not a full bottle. Water at this age is meant to help babies practice drinking from a cup and to complement solid foods. It’s not intended to replace breast milk or formula, which still provide the bulk of hydration and nutrition. At first, offering just 1–2 ounces of water a day is perfectly fine, and you can gradually increase it as your baby gets used to drinking from a cup.
3. How much water should a 7–9 month old drink?
At this stage, babies usually do well with around 2–8 ounces of water a day, especially when they’re eating solid foods. Water should be offered during mealtimes to help with swallowing and to rinse their mouths after eating. If you notice that your baby is drinking water during meals but then refusing milk feeds, you might want to dial back the water and focus on offering milk first, with water as a complement. Each baby’s needs can be different, so just keep an eye on how much they’re drinking and make sure they’re still getting enough milk.
4. What are signs of water intoxication in babies?
Water intoxication is rare but can happen if babies drink too much water. Symptoms include sleepiness, vomiting, puffiness, muscle cramps, or seizures. If you notice these signs, seek medical help immediately. Always be mindful of the amount of water your baby consumes.
5. Is RO water ok for babies, and do you need to boil it?
Reverse Osmosis (RO) water is generally safe for babies older than 6 months, provided it comes from a clean, well-maintained system. RO water removes many dissolved minerals, which is not usually a problem unless your baby needs additional minerals for health. However, it’s important to discuss with your pediatrician or dentist if you mainly use RO water, as it may lower fluoride levels, which are important for dental health.
Boiling RO water is typically unnecessary unless you're unsure about the safety of your water supply, like if you're using well water or are traveling to areas with questionable water quality. Boiling water helps to kill germs but doesn’t remove chemicals like lead, so it’s crucial to ensure that your RO system is properly maintained if you're not boiling it.
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