By: Adel Galal, Parnthub
Most healthy babies can start small amounts of plain water at around 6 months, usually when solid foods begin. Before then, breast milk or correctly prepared infant formula normally provides the fluid a baby needs.
Quick Answer: Babies can usually start drinking small amounts of water at around 6 months. From 6 to 12 months, the American Academy of Pediatrics and CDC give a general guide of about 4 to 8 ounces of water per day. Breast milk or infant formula should still provide most nutrition and hydration during the first year.
This article is for general information and education. It does not replace medical advice, diagnosis, or treatment.
The detail that matters is this: turning 6 months old does not mean a baby suddenly needs a bottle full of water.
Water is introduced slowly. Milk remains central.
There is also a major difference between plain water offered as a drink, water used to prepare formula, and fluids used when a baby is ill. Mixing those situations together is where unsafe advice starts.
For the wider first year feeding picture, see the Baby Care Guide and the Infant Feeding Chart.
Table of Contents
- Why Babies Under 6 Months Usually Do Not Need Water
- Why Too Much Water Can Be Harmful
- 1. Start Water at Around 6 Monthsrarely Need
- 2. Keep Water Amounts Small
- 3. Offer Water With Solid Foods
- 4. Teach Cup Drinking
- 5. Never Dilute Formula
- 6. Handle Hot Weather Carefully
- 7. Treat Illness and Dehydration Differently
- Water by Baby Age
- Plain Water, Formula Water and Rehydration Fluid
- Which Water Is Safe?
- Dehydration Warning Signs
- Common Parent Questions
- References and Sources
- Internal Links and Hub
- About the Author
- Frequently Asked Questions
Why do babies under 6 Months Usually Not Need Water?
A young baby already drinks a liquid diet.
Breast milk provides both nutrition and fluid. The World Health Organization recommends exclusive breastfeeding for the first 6 months, which means no additional foods or drinks, including water.
Formula also provides fluid when it is prepared exactly according to the manufacturer's instructions.
The American Academy of Pediatrics says healthy babies in the first 6 months do not need water or juice in addition to breast milk or formula unless a pediatrician gives different instructions.
So if you are wondering about water before 6 months, the normal rule is simple:
If you are still in the newborn feeding stage, the Newborn Feeding Schedule explains how milk feeding changes during the early weeks.
Why can too much water be harmful for a Young Baby?
There are two main problems.
First, water takes up room in a baby's small stomach without providing the calories and nutrients found in breast milk or formula.
A baby who fills up on water can drink less milk.
Second, too much water can disturb the balance of sodium and other electrolytes in the baby's body.
The American Academy of Pediatrics warns that excessive extra water or watered-down formula can cause a dangerous condition called water intoxication. Severe electrolyte disturbance can cause seizures.
That is why the phrase “it is only water” is not a safe feeding rule for young babies.
1. Start Small Amounts of Water at Around 6 Months
Around 6 months is the usual starting point for both complementary foods and small amounts of plain drinking water.
The AAP, CDC, NHS, and WHO all place the move toward complementary feeding at about this age.
Your baby does not need a large serving.
A few sips with food are a perfectly reasonable beginning.
At this stage, water for babies has two jobs.
It adds a small amount of fluid as solid food intake grows, and it lets the baby practise a new drinking skill.
The baby is learning how to sip, swallow water, and use a cup.
For starting solids, see Baby Weaning Food.
2. From 6 to 12 Months, Keep Water Amounts Small
The most useful current number comes from the American Academy of Pediatrics and CDC.
For babies from about 6 to 12 months, a general guide is:
about half to one cup in total
This is a guide, not a drinking target that every baby must finish.
Your baby may take only a few sips when cup drinking begins.
That can be normal if breast milk or formula intake is going well and the baby is otherwise healthy.
The most important rule for infant hydration during this age is that breast milk or formula remains the main drink.
CDC states that breast milk or infant formula remains the main source of nutrition from 6 to 12 months.
Is 8 Ounces of Water a Minimum?
No.
This is an easy number to misunderstand.
The AAP range of 4 to 8 ounces per day is general guidance. It is not an instruction to force every baby to finish a full cup each day.
Milk intake, solid food intake, climate, health, and the baby's own drinking skills all affect how much water the baby actually drinks.
Do not turn the water cup into homework.
3. Offer Water With Solid Foods
Meal time is the easiest place to introduce water with solids.
Current NHS guidance recommends offering sips of water from a cup with meals from around 6 months.
That fits naturally with complementary feeding.
Your baby eats.
You offer the cup.
The baby takes a sip, plays with it, spills some, or decides they are finished.
No pressure is needed.
As solid food gradually becomes a larger part of the diet, cup drinking also becomes more familiar.
4. Use Water to Teach Cup Drinking
Around 6 months is a good time to introduce the first cup baby will practise with.
The AAP says water can be offered from an open cup, straw cup, or training cup.
The NHS encourages an open cup or free flow cup without a valve because it helps babies practise sipping.
An open cup can be messy.
That is not a problem.
The first attempts may put more water on the tray than in the baby.
A simple routine works:
- Seat your baby upright and safely.
- Offer a small amount of water with the meal.
- Let the baby practise without pressure.
- Stop when the baby turns away or the meal ends.
- Keep normal breast milk or formula feeds.
Should I Give Water in a Bottle?
Once water is appropriate, a baby can physically drink it from a bottle.
But there is usually little benefit in creating another bottle habit when cup learning can begin instead.
The NHS recommends introducing a cup from around 6 months and discouraging bottle feeding after the first birthday.
A useful pattern is:
5. Never Add Extra Water to Formula
This is one of the most important safety rules in the article.
Water offered as a drink and water used to prepare formula are not the same issue.
Powdered formula and concentrated formula require a precise water amount.
CDC says to measure the water first, then add the amount of formula powder listed on the container.
Too much water means the bottle may not provide enough nutrition.
Too little water can place extra strain on the baby's kidneys and digestive system and can contribute to dehydration.
The AAP also warns that watered down formula can disturb electrolyte balance and cause serious illness.
Never dilute formula to:
- make the container last longer
- reduce calories
- make the bottle less filling
- help constipation without medical advice
- give a baby extra hydration
If your baby needs a different formula concentration for a medical reason, the healthcare team should give the exact plan.
What About Ready-to-Feed Formula?
Do not add water to ready-to-feed formula.
It is already prepared at the correct concentration.
The AAP specifically warns against adding water to non-concentrated ready-to-feed formula.
Always read the package because ready-to-feed formula, liquid concentrate, and powdered formula are prepared differently.
6. Hot Weather Does Not Automatically Mean Extra Water for Every Young Baby
This is one area where respected health systems do not word their advice exactly the same way.
WHO says exclusively breastfed babies younger than 6 months do not need water, even on hot days. Extra breastfeeding can meet increased thirst.
The AAP also says healthy babies in the first 6 months usually need only breast milk or formula unless a pediatrician advises otherwise.
Current NHS guidance includes a limited exception for formula fed babies younger than 6 months. It says they may sometimes need small sips of cooled boiled water in hot weather in addition to their normal formula.
That difference is a good reminder that infant feeding guidance can vary with local health systems and climate recommendations.
If your baby is younger than 6 months and you are concerned about heat or hydration, ask your child's healthcare professional what applies where you live.
Do not replace a milk feed with plain water.
7. Do Not Treat Infant Dehydration With Plain Water on Your Own
A baby with vomiting, diarrhea, fever, or poor feeding needs more thought than simply adding water.
Illness can cause the body to lose both water and electrolytes.
The correct fluid depends on the baby's age, feeding pattern, symptoms, and severity.
NHS dehydration guidance recommends continuing breast milk or formula and using oral rehydration solution when advised.
It also warns against weakening formula.
For a young baby, poor feeding or signs of dehydration deserve medical advice.
Do not try to solve significant dehydration by filling a bottle with plain water.
Plain Water, Formula Water and Rehydration Fluid Are Different
This distinction adds more value than simply memorizing “6 months.”
| Fluid | When It Is Used | Main Safety Rule |
|---|---|---|
| Plain Drinking Water | Usually introduced from around 6 months with meals. | Keep amounts small and do not replace needed milk feeds. |
| Water Used for Formula | Used to prepare powder or concentrated formula when required. | Use the exact amount stated on the formula instructions. |
| Ready to Feed Formula | Given directly according to package instructions. | Do not add water. |
| Oral Rehydration Solution | Sometimes recommended during vomiting, diarrhea, or dehydration. | Use it according to professional or product guidance rather than replacing it with homemade plain water treatment. |
How Much Water Should Babies Drink by Age?
| Age | Main Drink | Plain Water | Parent Focus |
|---|---|---|---|
| Birth to About 6 Months | Breast milk or correctly prepared infant formula | Usually none unless medically advised or local guidance gives a specific exception | Effective milk feeding, growth, wet diapers, and safe formula preparation |
| About 6 to 12 Months | Breast milk or infant formula remains the main drink | AAP and CDC guide: about 4 to 8 ounces daily | Offer small sips with meals and practise cup drinking |
| From 12 Months | Water becomes a regular main drink alongside an age-appropriate diet and milk | Offer regularly based on meals, thirst, activity, and climate | Build a normal water drinking habit |
This table is general guidance for healthy babies.
Premature babies and babies with kidney disease, heart disease, feeding problems, growth concerns, or a prescribed fluid plan need individualized advice.
Does Breast Milk Still Count as Hydration After 6 Months?
Yes.
Introducing water does not mean breast milk stops hydrating your baby.
WHO recommends continuing breastfeeding when complementary foods begin.
CDC likewise says breast milk or infant formula remains the main source of nutrition from 6 to 12 months.
Water is added.
Milk is not suddenly replaced.
For breastfeeding support, see Breastfeeding Newborn.
Should Water Come Before or After Milk?
During the first year, do not use water to intentionally delay or replace milk feeds that your baby still needs.
A practical pattern is to continue responsive breast milk or formula feeding and offer a little water alongside solid meals.
That makes the water part of eating practice rather than a substitute for nutrition.
If your baby has a medical feeding plan because of prematurity, reflux, growth problems, or another condition, use the plan from the healthcare team.
What Kind of Water Can a Baby Drink?
Use safe drinking water.
The details depend on where you live.
Current NHS guidance says babies older than 6 months can drink safe tap water without boiling it first in the United Kingdom.
CDC guidance for formula preparation says to use water from a safe source and contact local health authorities if you are unsure whether the tap water is safe.
Do not assume bottled water is automatically the best choice everywhere.
Local water quality, mineral content, and public health recommendations matter.
Can Babies Drink Juice Instead of Water?
Babies do not need juice.
The American Academy of Pediatrics recommends no fruit juice before 12 months.
The NHS also advises avoiding fruit juice and smoothies before the first birthday.
Plain water is the better cup habit to teach.
How Can I Tell if My Baby Is Dehydrated?
The American Academy of Pediatrics lists several signs parents should watch for in infants.
They include:
- fewer wet diapers than usual
- unusual sleepiness
- a sunken soft spot on the head
- few or no tears while crying
Dry mouth, poor feeding, repeated vomiting, or a baby who looks unusually unwell can also deserve medical attention.
Do not wait for every possible sign before calling.
Young babies can become unwell quickly.
The Newborn Care Basics guide covers feeding, diapers, alertness, and other daily signs worth watching in the early months.
What if My Baby Accidentally Drinks Water Before 6 Months?
A tiny accidental sip is different from repeatedly giving water or repeatedly diluting formula.
Do not panic over one small taste.
Stop offering plain water and return to normal breast milk or correctly prepared formula.
If a young baby drank a large amount of water, formula was repeatedly overdiluted, or the baby becomes unusually sleepy, irritable, vomits, behaves abnormally, or has a seizure, seek urgent medical advice.
The Four Question Water Check
When you ask when can babies drink water, use four questions.
| Check | Question |
|---|---|
| Age | Is my baby around 6 months or older? |
| Food | Has complementary feeding started? |
| Milk | Is breast milk or formula still the main drink? |
| Amount | Am I offering small sips rather than replacing a milk feed? |
If those four points fit, you are usually in the normal water introduction stage.
Conclusion: Start With Sips, Not a Water Target
So, when can babies drink water? For most healthy babies, plain water can begin at around 6 months when solid foods start. Offer small amounts from a cup and keep breast milk or formula as the main drink through the first year.
Your next step: when your baby begins solids, place a small open or straw cup of plain water beside the meal and let your baby practise. Do not force an amount, and never dilute formula to increase water intake.
References and Sources
-
American Academy of Pediatrics, HealthyChildren.org.
Recommended Drinks for Children Age 5 and Younger.
Gives the current AAP guidance of about 4 to 8 ounces of water per day from 6 to 12 months and discusses cup introduction.
https://www.healthychildren.org/English/healthy-living/nutrition/Pages/Recommended-Drinks-for-Young-Children-Ages-0-5.aspx -
Centers for Disease Control and Prevention.
Foods and Drinks to Encourage.
Updated April 1, 2026.
Confirms breast milk or infant formula plus about 4 to 8 ounces of water per day for babies from 6 to 12 months.
https://www.cdc.gov/infant-toddler-nutrition/foods-and-drinks/foods-and-drinks-to-encourage.html -
Centers for Disease Control and Prevention.
Infant Formula Preparation and Storage.
Covers safe water sources, measuring water before formula powder, and why formula should be mixed exactly as directed.
https://www.cdc.gov/infant-toddler-nutrition/formula-feeding/preparation-and-storage.html -
NHS.
Drinks and Cups for Babies and Young Children.
Covers offering water with meals from around 6 months, cup use, milk as the main drink, and the United Kingdom hot weather guidance for babies.
https://www.nhs.uk/baby/weaning-and-feeding/drinks-and-cups-for-babies-and-young-children/ -
World Health Organization.
Breastfeeding Questions and Answers.
States that exclusively breastfed babies do not need additional water during the first 6 months, including during hot weather.
https://www.who.int/news-room/questions-and-answers/item/breastfeeding
Internal Links and Hub
This topic sits inside the bigger first year feeding picture. These Parnthub guides can help you move from milk feeding to solids and cup drinking without losing sight of safe nutrition.
- Baby Care Guide for the main Parnthub hub covering newborn care, feeding, sleep, development, health, safety, and the first year.
- Infant Feeding Chart for breast milk, formula, solid food, and first-year feeding patterns from birth to 12 months.
- Baby Weaning Food for starting solids, safe textures, first foods, cup practice, and feeding progression from around 6 months.
- Breastfeeding Newborn for milk transfer, feeding cues, supply, diapers, hydration, and breastfeeding support.
- Newborn Feeding Schedule for early breast and formula feeding patterns and how much normal timing can vary.
- Newborn Care Basics for feeding, diapers, alertness, safe sleep, daily care, and signs that deserve professional advice.
For the broadest starting point, use the Baby Care Guide. If your baby is starting solids now, continue with Baby Weaning Food.
About the Author
Adel Galal is the founder and primary author of Parnthub. He is a father of four and grandfather of four with more than 33 years of parenting and grandparenting experience.
His parenting articles combine long family experience with careful review of current pediatric, infant feeding, breastfeeding, nutrition, and child safety guidance. His goal is to separate simple feeding rules from the situations where age, illness, formula preparation, or individual medical needs change the answer.
Adel is not a physician, pediatrician, dietitian, or other licensed healthcare professional. Parnthub content is informational and educational and does not replace medical diagnosis, treatment, infant feeding assessment, emergency care, or personalized advice from a qualified healthcare professional.
Learn more about Adel and Parnthub on the About Us page.
Frequently Asked Questions
When can babies drink water?
Most healthy babies can start small amounts of plain water at around 6 months, usually when solid foods begin. Breast milk or infant formula should remain the main drink through the first year.
How much water can a 6-month-old drink?
The American Academy of Pediatrics and CDC give a general range of about 4 to 8 ounces per day from 6 to 12 months. A new cup drinker may initially take much less.
Does my baby need to drink 8 ounces of water every day?
No. The 4 to 8 ounce range is general guidance, not a minimum quota. Breast milk or formula still provides most fluid during the first year.
Can babies drink water before 6 months?
Healthy babies under about 6 months rarely need plain water in addition to breast milk or formula unless a healthcare professional or relevant local guidance recommends it.
Can I give my breastfed baby water in hot weather?
WHO says exclusively breastfed babies under 6 months do not need extra water even in hot weather. Offer breastfeed more often if the baby seems thirsty.
Can formula-fed babies have water in hot weather?
Guidance varies by country. Current NHS guidance says some formula-fed babies under 6 months may need small sips of cooled boiled water in hot weather. Other guidance advises no extra water unless medically recommended. Ask your baby's healthcare professional if unsure.
Should water replace a breast milk or formula feed?
No. During the first year, breast milk or infant formula remains the main source of nutrition. Water is a small additional drink once solids begin.
Can I add extra water to baby formula?
No. Use exactly the amount of water stated on the formula instructions. Adding extra water can reduce nutrition and disturb the baby's electrolyte balance.
Do I add water to ready to feed formula?
No. Ready to feed formula is already prepared at the correct concentration and should not be diluted with water.
Should I measure formula powder or water first?
CDC says to measure the correct amount of safe water first, then add the formula powder according to the instructions on the container.
Should babies drink water with solid food?
Yes. From around 6 months, offering small sips of water with meals is a simple way to introduce water and practise cup drinking.
What cup is best for a baby starting water?
An open cup or straw cup can work well. NHS guidance also recommends a free flow cup without a valve so the baby learns to sip rather than rely on sucking.
Can babies drink juice instead of water?
Babies do not need juice. The American Academy of Pediatrics recommends no fruit juice before 12 months. Plain water is a better everyday cup drink.
Can I give plain water when my baby has diarrhea or vomiting?
Do not rely on plain water alone to treat dehydration in a baby. Continue normal milk feeding as advised and ask a healthcare professional whether an oral rehydration solution or medical assessment is needed.
What are signs of dehydration in a baby?
Warning signs include fewer wet diapers, unusual sleepiness, a sunken soft spot, few or no tears, dry mouth, poor feeding, or a baby who seems increasingly unwell. Contact a healthcare professional if you are concerned.
What if my baby accidentally has a sip of water before 6 months?
A tiny accidental sip is different from routinely giving water or diluting formula. Return to normal milk feeding. Seek medical advice if a young baby drank a large amount or develops unusual symptoms.
