How Much Water Do Babies Really Need? A Month-by-Month Guide

Hydration plays a vital role in your baby’s growth and development. Fluids help regulate body temperature, support digestion, transport nutrients, and keep organs functioning properly. Because babies are still developing and have higher water needs relative to their body weight, staying well-hydrated is essential from day one.

However, hydration for babies doesn’t always mean giving them plain water—especially during the first six months of life. For most babies, breastmilk or properly prepared formula is the only fluid they need early on. The right amount of fluid depends on your baby’s age, feeding method, and health. To help parents stay informed, we’ve included a free, printable “Baby Hydration Chart (0–12 Months)” that outlines fluid needs and safe water practices for every stage.

Why Baby Hydration Is Different From Adult Hydration

Unlike adults, babies have a much higher water-to-body-weight ratio, meaning their bodies require more fluid per pound to stay hydrated. At the same time, their kidneys are still maturing, which makes them more vulnerable to both dehydration and overhydration. Giving a young baby too much water can dilute their blood sodium levels—a condition called water intoxication. That’s why it’s so important to match your baby’s fluid intake with their age and nutritional needs.

Hydration Needs by Age: Month-by-Month Breakdown

0–3 Months

Fluid source: Breastmilk or formula only.

Babies do not need plain water during this stage—even in hot weather.

Formula-fed babies depend on an accurate water-to-formula ratio for proper hydration.

⚠️ Plain water can be dangerous for newborns and may lead to water intoxication.

4–6 Months

Continue with breastmilk or formula as the only fluid unless your pediatrician advises otherwise.

Some babies may drink slightly more formula or breastmilk if they’re growing or in warmer environments.

Learn to distinguish thirst cues from hunger cues (e.g., sucking on hands, rooting).

Related reading: Signs of Dehydration in Babies and How to Prevent It

6–9 Months

Begin introducing small sips of plain water—about 1–2 oz per meal is typically safe.

Breastmilk or formula should still be the primary fluid source.

When giving water, use distilled water—it’s free of fluoride, heavy metals, and minerals that can upset sensitive digestive systems.

9–12 Months

Gradually increase daily water intake to 4–8 oz per day.

Offer water in a sippy cup or open cup alongside meals.

Avoid sugary drinks or flavored waters, which can interfere with hydration and dental health.

Continue offering breastmilk or formula to meet nutritional and fluid needs.

Feeding Method Matters: Breastfed vs. Formula-Fed Babies

Hydration varies based on how your baby is fed:

Breastfed babies receive all the hydration they need from breastmilk alone until around 6 months of age.

Formula-fed babies are more sensitive to water quality and proper mixing. Using water with high mineral content or unsafe contaminants can lead to dehydration or digestion issues.

For formula-fed babies, always use distilled water to mix formula safely. It ensures accurate nutrition and protects developing kidneys from excess minerals or chemicals found in tap or spring water.

Warning Signs Your Baby May Need More Fluids

While healthy feeding habits usually meet a baby's hydration needs, there are situations where extra attention is needed. Watch for these signs of mild dehydration:

Fewer wet diapers

Dry mouth or lips

Unusual fussiness or tiredness

Your baby may need more fluids if they are:

Running a fever

Experiencing diarrhea or vomiting

Living in or visiting hot climates

Going through a growth spurt

Always consult your pediatrician before offering additional fluids or rehydration solutions.

Baby Hydration Chart (0–12 Months)

To make hydration easier to track, we’ve created a downloadable Baby Hydration Chart that includes:

Recommended fluid types by age

Approximate daily fluid needs

Water safety tips

Notes for breastfed vs. formula-fed infants

Conclusion

Understanding your baby’s hydration needs is a key part of supporting their growth and comfort. From birth to one year, your baby’s fluid requirements will evolve—starting with breastmilk or formula alone and gradually incorporating small amounts of plain water. For formula-fed babies, using distilled water helps ensure safety and consistent nutrition without adding stress to developing organs.

Staying informed—and prepared—goes a long way in protecting your baby’s health. For more hydration tips, feeding advice, and expert-backed guidance, be sure to Vist the Bay-Bay Water