Ans: You can use tap water to prepare your baby's formula as long as you boil it. This is especially recommended for babies younger than 12 months. Tap water contains several impurities that only boiling can remove.  Even if you have a water purification system in your home, you should boil your baby's water before you use it to make the formula milk because such purifiers do not remove all impurities from water.  Remember, you should not feed your baby unboiled tap water before they're a year old. Also, do not give them any water before they're 6 months old.