Newborn babies do just fine with formula or breast milk; drinking water is not recommended until about six-12 months (too much water can cause jaundice or intoxication). However, when making bottles it is imperative to use pure water. While most of the medical world pushes breast feeding, many moms opt for formula.  Or in fact, must use the substitute for health reasons. Whatever the reason behind not using breast milk, attention must be focused on one crucial ingredient to formula: water.  The World Health Organization states, concentrations of nutrient minerals in drinking water may contribute significantly to the total trace element and mineral intake of infants and young children applicable to formula-fed infants during the first months of life, who may be the most vulnerable group affected by excessive concentrations of nutrients or contaminants in drinking water.

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Formula can come ready to drink which parents can be assured is safe.  Formula also comes in powder mixture, which water is mixed with. Because the latter infants will be in taking so much water through formula, safety of that

water should be the parents’s main concern.
Also, homes with water purification systems will be on the safe side. Contamination of water needs to be limited.
Pure drinking water can also aid in healthy teeth and gums. Many toddlers need a bottle to go to sleep with or they get antsy. But, giving a bottle of juice or ice tea can cause decay. A bottle of water is suggested instead.
According to TodaysParent.com, until babies begin to eat food, they will get all of the nutrition they need from breast milk and formula.  But, the site also says once a baby is older and drinking from a cup, water is preferred over juice as it satisfies thirst. (Plus, it will start a healthy water habit early!)