The Short Answer
Babies under 6 months should not be given water — not even a few sips. From around 6 months, when solid foods begin, small amounts of water (60–120 ml / 2–4 oz per day) can be offered with meals. This recommendation is consistent across the WHO, AAP, NHS, and Helsedirektoratet.
Why No Water Before 6 Months?
Giving water to a baby under 6 months can be dangerous:
- Water intoxication: A baby's kidneys are immature and cannot process excess water. Even small amounts (as little as 2–3 oz) can dilute sodium levels in the blood, leading to hyponatraemia — a potentially life-threatening condition
- Displaces nutrition: Water fills a tiny stomach without providing calories, fat, or protein. Babies who drink water eat less breast milk or formula, risking weight faltering and nutrient deficiency
- Electrolyte imbalance: Low sodium can cause seizures, brain damage, and in severe cases, death
Breast milk and formula are approximately 87% water and provide complete hydration for infants under 6 months. No additional fluids are needed.
When Can Babies Start Water?
| Age | Water recommendation |
|---|---|
| 0–6 months | No water (breast milk/formula only) |
| 6–12 months | Up to 120 ml (4 oz) per day with meals |
| 12+ months | Up to 240 ml (8 oz) per day; water as primary drink alongside whole milk |
How to Offer Water From 6 Months
- Use an open cup or free-flow sippy cup — the NHS recommends open cups from 6 months to support oral development and reduce prolonged bottle use
- Offer small sips with meals, not between them
- Tap water is fine for babies over 6 months in countries with safe water supplies (including Norway and the UK)
- Water does not need to be boiled after 6 months in countries with safe tap water
What About Juice, Squash, or Other Drinks?
- Fruit juice: Not recommended under 12 months (NHS, AAP). High sugar content, promotes tooth decay, displaces nutrition
- Squash and flavoured drinks: Not appropriate for babies — too much sugar and additives
- Herbal teas: Not recommended under 12 months
- Cow's milk as main drink: Not before 12 months (may be used in cooking from 6 months)
Hot Weather and Illness
Even in hot weather, healthy babies under 6 months do not need water. If breastfeeding, offer the breast more frequently — breast milk provides all hydration needed. If formula-feeding, offer the normal amount of formula more frequently.
During illness with vomiting or diarrhoea, consult your doctor. Oral rehydration solutions (like Dioralyte) may be recommended — do not give water alone as a rehydration measure.
Explore Tools
Track feeds and hydration alongside solids introduction with our SmartStart Food Guide.
Related Articles
- When Can Babies Start Eating Solid Food?
- What Foods to Avoid for Babies Under 1
- How to Start Baby-Led Weaning
Sources
- American Academy of Pediatrics (AAP) — Recommended Drinks for Children Under 5
- NHS — What to feed young children
- World Health Organization (WHO) — Complementary Feeding
- Helsedirektoratet — Drikke til spedbarnet