Before we answer that question, first we must understand what is mineral water. Mineral water is water from a mineral spring that contains various minerals, such as salts and sulfur compounds.

There are two types of Mineral water, soft and hard. Defined by the World Health Organization (WHO), water containing high levels of calcium and magnesium–over 120mg/L, , is known as “hard water”. Water containing smaller amounts of these minerals–less than 120mg/L–is known as “soft water.”

Newborn baby’s internal organs have not yet fully developed so hard water can put a burden on their kidneys and digestive systems as it is harder to process the minerals. This may cause diarrhea, stomach aches or other physical conditions.

The baby’s internal organs become developed around 2 to 3 years old, so before then, it is best not to give your baby hard mineral water in powdered milk and never feed the baby directly.

Soft mineral water however, is generally safe for newborns as the mineral content is lower. However, most powdered milk are produced with the optimum levels of minerals so usually the producers will recommend a lower mineral content water to use with their products.

In short, Yes, it is fine to use mineral water to make powdered milk formula, but always check the labels of both the powdered milk and mineral water for the mineral content. It is important that the minerals in the water is the recommended amount for your newborn’s health.