My daughter is 4mths old..at what age can i give her water and how much?

Wait until 6 months: Babies less than 6 months get adequate hydration from breast milk or formula. They don't need water, they need the nutrition that comes from formula and breast milk for growth and brain development. It's ok to give occasional sips after 6 months but be careful. Overdoing it can cause dangerous disruptions in sodium levels.