When Can Babies Drink Water? Ages, Amounts, and Safety

The short answer

For most babies, small drinks of plain water begin around six months, alongside solid foods. Before then, breast milk or correctly prepared infant formula normally supplies the fluid they need. A newborn should not routinely receive a bottle of water. Ask your baby's clinician about exceptions, particularly during illness or extreme heat.

The first cup can be a lovely, messy milestone. It does not mean milk feeds suddenly become less important, and it does not need to become another daily target to worry about. Here is how to separate normal cup practice from a hydration concern.

Before six months: milk comes first

The American Academy of Pediatrics explains that babies under six months do not need extra water unless their pediatrician advises it. Too much water can disturb the balance of salts in a baby's body. Watering down formula also reduces the nutrition in a feed.

That distinction matters when advice comes from a well-meaning relative: water used in the correct formula recipe is different from an extra water drink. Neither a thirsty-looking baby nor a warm afternoon is a reason to change the recipe yourself.

If you are wondering whether your newborn is getting enough milk, bring the question back to feeding. Tell your midwife, health visitor, or pediatrician what you have noticed about feeds, nappies, and alertness. Our guide to a newborn who still seems hungry after feeding can help you organize those observations without replacing an assessment.

Around six months: introduce a little cup practice

Once solids begin around six months, the NHS recommends offering sips of water with meals. It suggests an open cup or a free-flow cup without a valve. Breast milk or infant formula remains part of feeding throughout the first year.

A practical starting point is to bring a small cup to a meal you are already supervising. Help your baby hold it, offer a small sip, and let them stop. Keep a cloth nearby. Some water will probably reach their clothes before it reaches their mouth; that is useful information about cup practice, not evidence that you should pour faster.

Think of the first attempts as a shared activity. You might say, “Here is your water,” show the cup, and pause when your baby turns away. There is no need to chase their mouth around the tray or persuade them to finish everything you poured.

Our guide to starting solids covers the broader transition. If your baby has swallowing difficulties, a feeding tube, a medical condition, or an individual fluid plan, ask their care team how cup practice should fit that plan.

How much water can a six- to twelve-month-old have?

The CDC lists 4–8 US fluid ounces of water a day for babies aged six to twelve months, approximately 120–240 mL, alongside breast milk or formula. This is a daily amount, not an amount to offer at every meal or an instruction to replace a milk feed.

Use the guidance as context for a conversation if you are unsure. A baby spilling most of a first cup is a different situation from a baby repeatedly drinking large cups and taking much less milk. Explain which situation you are seeing rather than trying to solve both with the same number.

For example, imagine an eight-month-old practicing at lunch. You offer a little water, they take a few sips, and the cup goes down while you continue the meal. Later, their usual milk feeding remains available. This is an example of how water can fit alongside feeding, not a prescribed schedule.

If you track drinks, distinguish what you offered from what your baby actually drank. A cup tipped onto the high-chair tray should not appear in your notes as a completed drink. An honest approximation is more useful than an exact-looking total built from spilled water.

What about hot weather?

You may see different advice from reputable organizations. US AAP guidance generally advises no extra water under six months unless a pediatrician recommends it. The UK NHS says fully breastfed babies do not need water before solids, even in hot weather, but formula-fed babies under six months may need small sips of cooled boiled water in hot weather as well as their usual feeds.

These are regional recommendations, not two instructions to combine into your own new rule. For a young baby, ask your local clinician which advice applies, how much to offer if needed, and what changes should prompt help. Never dilute formula to make a “more hydrating” bottle.

If you are traveling, make the question specific: your baby's age, milk feeding, destination, and any health needs. A general adult hydration tip is not an infant feeding plan.

Keep drinking water separate from formula preparation

The CDC's formula-preparation guidance says to measure the water first and use the exact quantity of powder specified. Too much or too little water can cause harm. Follow current local preparation advice and any additional instructions for a premature, very young, or immunocompromised baby.

There are really two separate questions to ask: “What can my baby drink?” and “How do I prepare this particular formula safely?” Advice about a sip from a cup does not answer the second question. Keep the preparation instructions with the formula so anyone sharing care can check them.

For bottles made in advance, see our formula-storage guide. Do not use a water drink to stretch out the time until an unsafe leftover bottle can be offered again.

When the question is possible dehydration

Seek urgent medical advice if your baby has fewer wet nappies than usual, unusual drowsiness, a sunken soft spot, or other signs of dehydration. If they are difficult to wake, struggling to breathe, or have blue, grey, or blotchy skin, get emergency help. These signs are described in the NHS dehydration guidance.

A baby who is unwell needs an age-appropriate assessment, not a larger cup experiment. Ask a clinician whether a rehydration solution or another feeding plan is needed. Do not delay calling while trying to reach an app's fluid total.

When you call, a short description helps: “My baby is this age, has taken this much less milk than usual, and their last wet nappy was at this time.” You can give that information even if you have never used a tracker. Avoid waiting to build a perfect record before seeking help.

Common questions

Can water replace a night feed?

Do not replace an infant's needed milk feed with water to encourage longer sleep. Feeding and night-weaning decisions depend on the baby's individual needs. Our night-weaning guide explains questions to discuss before changing feeds.

Does boiling water make it suitable for a newborn drink?

Boiling addresses some water-safety concerns; it does not change a newborn's nutritional needs or remove the risks of too much water. Age and clinical advice still matter.

My baby refuses the cup. Have we missed the window?

One unsuccessful attempt is not a deadline missed. Offer another calm opportunity alongside a meal, and ask for feeding support if drinking seems painful, difficult, or consistently concerning. There is no need to turn a small new skill into a contest.

Sources checked September 30, 2026. General education from the Bambii Editorial Team; not individually reviewed by a clinician. Read our editorial standards or send a correction to team@bambii.app. Cover illustration generated with AI.