Can a 6-Month-Old Drink Plain Water?
Yes, a 6-month-old infant can drink small amounts of plain water, but human milk or infant formula remains sufficient to meet all fluid requirements at this age. 1, 2
Primary Fluid Requirements
Human milk or infant formula provides complete hydration for infants up to 6 months of age and remains the primary fluid source even after 6 months. 1, 2
The American Academy of Pediatrics explicitly states that no additional fluids are nutritionally necessary for infants under 6 months when adequately breastfed or formula-fed. 1
Breastfed infants do not require water supplementation, even in hot weather, as breast milk adjusts its composition to meet hydration needs. 3
When Plain Water Can Be Introduced
After 6 months of age, when solid foods are introduced, small amounts of plain water can be offered alongside continued breast milk or formula. 1, 2
Water should be offered in a cup rather than a bottle to promote proper feeding development and reduce dental risks. 1
The amount should be modest, as excessive water intake can displace nutrient-dense breast milk or formula, potentially leading to malnutrition. 1
Critical Safety Considerations
Water intoxication is a real danger in young infants, particularly those under 6 months, as their kidneys are immature and cannot handle large water loads. 3
Excessive plain water can cause hyponatremia (low blood sodium), which can lead to seizures and other serious complications in infants. 1
Water supplementation before 6 months may reduce breast milk supply and lead to early weaning by decreasing nursing frequency. 3, 4
Practical Approach After 6 Months
Offer water in small amounts (a few ounces) with meals once solid foods are introduced, typically around 6 months. 1, 2
Continue prioritizing breast milk or formula as the primary fluid source throughout the first year of life. 1, 2
Tap water is acceptable and contributes to fluoride intake for dental health. 2
Monitor for adequate wet diapers (6-8 per day) to ensure proper hydration status. 3
What to Avoid
Never give fruit juice to infants under 12 months of age unless specifically indicated for a medical condition like constipation. 1, 2
Avoid using water or any liquid other than breast milk/formula in bottles at bedtime to prevent dental caries. 1, 2
Do not allow infants to carry around bottles or cups of water throughout the day, as this can displace nutritional intake. 1
Common Pitfalls
Parents often overestimate the need for additional fluids in infants, particularly in warm weather, when breast milk or formula alone remains adequate. 3, 4
Some caregivers may offer excessive water thinking it's harmless, not recognizing the risk of water intoxication in young infants. 3
The shift toward lower-sodium infant formulas and foods means infants with certain conditions (like cystic fibrosis) may need electrolyte monitoring, but healthy infants do not require sodium supplementation through additional fluids. 5