At 6 months old, your baby can start having small sips of water, but the amounts should stay modest: 4 to 8 ounces per day, spread across the day. Before 6 months, babies get all the hydration they need from breast milk or formula. Once solids enter the picture, water serves as a complement to meals, not a replacement for milk feeds.
How Much Water and How Often
The CDC recommends 4 to 8 ounces of water per day for babies between 6 and 12 months old. That’s roughly half a cup to one cup total for the entire day. You don’t need to hit that amount on day one. Start with a few sips at mealtimes and gradually work up as your baby gets comfortable with a cup.
The easiest approach is to offer a small amount of water alongside solid food meals. If your baby is eating solids twice a day, offer an ounce or two at each sitting. Water at this age isn’t about hydration so much as getting your baby used to drinking from a cup and helping wash down new foods. Breast milk or formula remains the primary source of both calories and fluids through the entire first year.
Why Small Amounts Matter
A baby’s kidneys are tiny. At birth, they’re roughly the size of a grape, compared to an adult kidney that’s closer to the size of an avocado. Those small kidneys can’t flush out excess fluid the way yours can. When a baby takes in too much water, it dilutes the sodium in their bloodstream, a condition called hyponatremia (sometimes referred to as water intoxication). Symptoms can include irritability, drowsiness, low body temperature, and in severe cases, seizures.
This is why water should never replace a breast milk or formula feeding. If your baby seems extra thirsty, the answer at this age is usually more milk, not more water. Sticking to that 4 to 8 ounce daily range keeps things safe while still letting your baby practice drinking.
What Kind of Cup to Use
Six months is a great time to introduce an open cup or a straw cup. Both options help develop oral motor skills better than a sippy cup with a spout, which encourages the same sucking motion as a bottle. You’ll want to hold the cup for your baby at first and expect plenty of spills. A small, lightweight cup that’s easy for little hands to grip works best.
Don’t worry about how much your baby actually swallows in the first few weeks. The goal is exposure and practice. Many babies will take one or two sips and push the cup away, and that’s perfectly fine.
Tap Water, Bottled Water, or Boiled Water
For a healthy 6-month-old, regular tap water is safe to use as long as your local water supply meets safety standards. You don’t need to boil it first. The American Academy of Pediatrics recommends boiling water for infants under 2 months, premature babies, and those with weakened immune systems, but a healthy baby at 6 months doesn’t fall into those categories.
If you’re concerned about your local water quality, check your municipality’s annual water quality report or use a home filter. Bottled water is fine in a pinch, but it’s not necessary as a routine choice, and some bottled waters contain added minerals that your baby doesn’t need.
Fluoride in Your Baby’s Water
Fluoride supports healthy tooth development, and your baby’s first teeth are likely appearing right around 6 months. If your tap water contains fluoride (most public water systems in the U.S. do), the small amount your baby drinks each day contributes to their intake without any extra steps needed.
If your water supply has little or no fluoride, the American Dental Association recommends a daily fluoride supplement of 0.25 mg for children from 6 months to 3 years old. Your pediatrician or dentist can check whether your water is fluoridated and advise on whether a supplement makes sense. If you’re using well water, it’s worth getting it tested, since fluoride levels in wells vary widely.
Timing Water Around Milk Feeds
The key principle is simple: milk first, water second. Offer breast milk or formula as the main feed, then give water with or after solid foods. If you offer water before a milk feeding, your baby may fill up on it and take in fewer calories and nutrients from milk, which is still providing the bulk of their nutrition at this stage.
A typical routine might look like this: nurse or bottle-feed in the morning, then offer solids with a few sips of water at a mid-morning or lunchtime meal. Repeat with an afternoon or evening solids session. Between meals, stick with breast milk or formula for hydration. On hot days or when your baby seems fussy after eating thick or salty foods, an extra ounce of water is fine, but you don’t need to push it.
Signs Your Baby Is Getting Enough Fluids
At 6 months, you’re still counting wet diapers as your main hydration gauge. Four to six wet diapers a day signals your baby is well hydrated. The urine should be pale yellow and not strongly concentrated. If your baby is producing fewer wet diapers than usual, has a dry mouth, or seems unusually lethargic, those are signs to increase milk feeds and check in with your pediatrician.
Water at this age is a supporting player. It helps your baby learn a new skill, makes mealtimes smoother, and contributes a tiny bit of extra hydration as solids become part of the routine. Keep it casual, keep the amounts small, and let your baby set the pace.