How Much Water Should You Drink While Breastfeeding?

What does the evidence say about water intake while breastfeeding?

1. The Institute of Medicine's recommended total water intake for breastfeeding women is about 3.8 liters a day from all fluids and foods combined, roughly 1.1 liters more than the recommendation for women who aren't breastfeeding. 1
2. In a study of nursing mothers, those who were exclusively breastfeeding had the lowest water balance of any group studied, and only about 76% met recommended fluid intake levels, suggesting many breastfeeding parents fall short rather than overdo it. 2
3. Drinking additional fluids beyond what satisfies thirst does not produce additional breast milk; the standard advice is to drink enough to quench thirst or a little more, such as a glass of water with meals and each nursing session. 3
4. Water toxicity from drinking far more fluid than needed is described as rare in healthy adults, but standard guidance still centers on thirst-driven intake rather than forcing large amounts of extra water. 3
5. Breastfed babies don't need supplemental water even in hot weather, since breast milk itself contains the right balance of water as long as feeding happens at regular intervals, a distinction worth knowing separately from how much the parent drinks. 4

How water intake changes by nursing stage

• Early weeks. In the early postpartum weeks, thirst is often intense while your milk supply establishes, so keeping water within reach during feeds is a simple habit to build.
• Established nursing. Once breastfeeding is well established, matching your fluid intake to thirst, rather than chasing a strict number, is still the standard approach, since going well beyond thirst hasn't been shown to make more milk.
• Weaning. As nursing sessions become less frequent later in the postpartum months, your fluid needs will naturally shift too; continuing to drink to thirst is still the simplest guide.