How much water should I give my baby when starting solids? A guide to safe infant hydration

October 22, 2025 •

4 min read

The American Academy of Pediatrics recommends introducing water in small amounts around 6 months of age, when babies typically start solids. This new milestone for your infant raises a common question for parents: how much water should I give my baby when starting solids? The answer involves moderation and a focus on practice over hydration initially.

Quick Summary

This article details safe practices for giving babies water, including age-appropriate amounts and methods. It explains why breast milk and formula remain the primary sources of hydration during the first year, provides tips for introducing a cup, and outlines how to recognize signs of dehydration.

Key Points

Start after 6 months: You can introduce water when your baby starts solids, but never before 6 months old.
Prioritize milk: Breast milk or formula must remain your baby's primary source of hydration and nutrition until they are at least one year old.
Practice, not hydration: The initial sips of water are for practicing cup drinking and familiarizing your baby with the taste, not for meeting their hydration needs.
Offer small amounts: Offer just a few sips (e.g., 2-4 oz total per day) with meals to avoid filling them up.
Use an open cup: Introducing an open or straw cup helps with oral motor skill development.
Boil tap water: It is often recommended to boil and cool tap water for babies under 12 months.

Why Babies Need to Wait for Water

For the first six months of a baby's life, breast milk or formula provides all the necessary fluid and nutrients. A baby's developing kidneys are not mature enough to process plain water effectively. Introducing water too early can have serious consequences, such as a dangerous condition called hyponatremia, or 'water intoxication,' where the sodium levels in the bloodstream are dangerously diluted. This is because an infant's small, grape-sized kidneys can easily become overwhelmed by excess fluid. Additionally, filling a baby's stomach with water can reduce their intake of breast milk or formula, which are far more nutritionally dense and critical for their growth.

The Transition to Water at 6 Months

Around the six-month mark, as you begin introducing purees or baby-led weaning, you can also start offering small amounts of water. The primary purpose of this initial water intake is not to hydrate, but to familiarize your baby with the taste of water and help them practice drinking from a cup. Breast milk or formula should still be their main drink and primary source of hydration until their first birthday.

Recommended Amounts for Infants (6-12 Months)

According to the American Academy of Pediatrics, you can offer up to 4-8 ounces of water per day. However, many experts, like Solid Starts, suggest limiting this to less than 2-4 ounces a day to ensure it doesn't displace valuable nutrition. The key is to offer small sips at mealtimes rather than a large volume at once. Don't worry if your baby doesn't show much interest at first; this is normal.

How to Introduce a Cup

Offering water in a cup is not just about hydration; it's a developmental step. Starting with an open cup or a straw cup can help your baby practice important oral motor skills.

Tips for cup training:

Start with a small, easy-to-hold cup. Non-breakable cups are ideal for inevitable spills.
Demonstrate how to drink. Your baby loves to imitate you, so show them how it's done.
Offer small amounts. Only put a little water in the cup at a time to minimize mess and waste.
Be patient. Spilling is part of the learning process. Gently guide the cup and help them feel the water on their lips.

Water Safety and Sources

Making sure the water you offer is safe is essential. The recommendations for water safety can vary by region. In some areas, it is recommended to boil and cool tap water for babies under 12 months.

Best water practices:

Tap water: Many health organizations recommend using regular tap water for babies over six months, especially if it's fluoridated, to help prevent future tooth decay. Always check local guidelines.
Boiled water: If you are using tap water for a baby under 12 months, it is often advised to boil it first, then cool it completely before offering.
Purified or distilled water: These are also safe options but can lack the beneficial fluoride found in many municipal tap water supplies. If you use distilled water for formula, follow instructions to ensure the right balance of nutrients.

Signs of Adequate Hydration and Dehydration

For a baby starting solids, a few sips of water won't drastically affect hydration status. The best indicator of proper hydration continues to be breast milk or formula intake and the number of wet diapers.

Signs of proper hydration (in babies over 6 months):

At least 4-6 good, wet diapers in 24 hours.
Urine is pale and not dark yellow.
Baby is alert and content.

Signs of dehydration:

Fewer than 3 wet diapers per day.
Dry mouth or lips.
Sunken soft spot (fontanelle).
Crying with few or no tears.
Lethargy or unusual fussiness.

If you observe any signs of dehydration, contact your pediatrician immediately.

Hydration Comparison: 0-12 Months


Feature	0-6 Months	6-12 Months
Primary Hydration Source	Breast milk or formula	Breast milk or formula (primary)
Water Introduction	No plain water	Small amounts at mealtimes
Recommended Water Intake	None	4-8 ounces per day, but often less is fine
Purpose of Water	N/A	Practice drinking, familiarize with taste
Cup Drinking	N/A	Encourage use of open or sippy cup

Conclusion

Introducing water to your baby is an exciting step, but it's important to remember that it is a supplemental drink for infants starting solids, not a replacement for breast milk or formula. By offering small, supervised sips from an appropriate cup, you can help your baby develop new skills while still prioritizing their main nutritional source. As always, if you have any concerns about your baby's hydration or diet, consult with your pediatrician. Following these guidelines will ensure a safe and healthy transition as your baby explores new tastes and textures.

For more detailed information, consult authoritative sources such as HealthyChildren.org, the official website of the American Academy of Pediatrics.

Frequently Asked Questions

No, it is not recommended to give plain water to babies under 6 months. Their kidneys are not mature enough to process it effectively, and it can lead to a dangerous condition called water intoxication. Breast milk or formula provides all the hydration they need.

The best indicators are plenty of wet diapers (at least 4-6 in 24 hours), pale-colored urine, and an alert, content demeanor. If you notice fewer wet diapers or signs of dehydration, consult your pediatrician.

Start with an open cup or a straw cup. This encourages the development of essential oral motor skills. While messy at first, it's a critical part of their learning process.

Some health guidelines recommend boiling and cooling tap water for babies under 12 months to ensure it is safe. Check with your local health authority or pediatrician for specific recommendations regarding your water supply.

It is very common for babies to be uninterested in plain water initially. Continue to offer small sips with meals. Remember, their primary hydration comes from breast milk or formula at this age, so it's not a concern if they don't drink much water.

No, you should not give babies juice or any sugar-sweetened beverages. Water should be plain. The American Academy of Pediatrics recommends avoiding juice for children under 12 months.

You can try adding fun elements, like a fruit or herb for infused water, or simply model good behavior by drinking water yourself. Make it a game or use a reusable straw to pique their interest.