Bottles and nipples should be as clean as possible. If you normally wash dishes with unchlorinated water or if your baby is a preemie or has weakened immunity, everything needs to be boiled. Bring a pot of water to a full, rolling boil and drop in nipples, bottles, and other utensils that come into contact with your child's food. Let these items boil for five minutes. After everything's cooled, wash your hands well with soap and prepare the bottles.

This boiling quickly wears out bottle nipples, so check and replace them often. Also replace any plastic bottles that are marked with the number seven recycling symbol or the mark “PC.”

If you live in a city with chlorinated water, you need to boil only new nipples, just once, to remove any chemicals left over from the manufacturing process. After the first use, you can wash them in the sink or top rack of the dishwasher. Repeated boilings can lead to a premature deterioration of the material. Read the instructions that come with your bottle nipples. Some manufacturers don't recommend nipples be washed in the dishwasher at all. Be sure to remove any old formula that might clog the hole in the nipple. Those little holes can plug easily, so force some soapy water through them until they squirt freely under pressure. Rinse everything with hot water.

Water

The formula you choose is only part of what your baby will be getting in her bottle. The other part is water, and safe water is vital for babies using formula.

How can you be sure your water is safe enough? As a rule, if your city's water supply meets federal and state guidelines for safety, it should be fine for use in formula preparation. There are exceptions, however, so have your water tested if you live in rural areas or have had seasonal thaws or floods. Pay attention to local newscasts; your waterworks issues alerts whenever your tap water may be dangerous to small children.

Many new parents choose bottled water for their babies’ formula, but don't be fooled into assuming it's better than the water coming out of your tap at home. While the FDA regulates bottled water that crosses state lines, the Environmental Protection Agency is charged with keeping tap water clean and safe. In the end, the standards used by one agency are not all that different from those used by the other.

Wipe the top of the formula can off with a clean cloth before opening. You can be confident that the contents of the can are sanitary, but you don't know what's been on the outside.

But what about those bottled waters that feature a picture of a happy baby? The name and label don't mean much. Three-dollar-per-gallon “baby water” is not necessarily any better than ninety-nine-cent-per-gallon “drinking water” or way-less-than-one-cent-per-gallon tap water. When you throw in the plastic bottles that have to be recycled or buried in the landfill, tap water seems to be the clear winner.

Yet there is a chance that tap water may have too much of a good thing: fluoride. In 2007, the Centers for Disease Control warned parents that using fluoridated tap water to mix infant formula, in addition to using fluoride-rich toothpaste or other fluoride sources, could lead to mild enamel fluorosis, or white, patchy discoloration, of children's teeth. So if your local water supply is heavily fluoridated, you might want to consider using bottled water that has been distilled, purified, deionozed, demineralized, or prepared through reverse osmosis to reduce fluoride content. At the same time, don't shy away from all fluoride; it helps prevents cavities.

If you are unsure of your tap water, a water filter is another option. A simple pitcher purifier can be purchased cheaply and can hold enough water for a day's worth of formula. You can also install water-filtering systems on your taps or on the water supply to your entire house. If you choose to filter your water at home, remember to change your filter cartridges regularly. Old filter cartridges can be an ideal breeding ground for germs.

If you live in an older house, your pipes may contain traces of lead or other impurities. Let the water run for a few seconds before you use it to remove these contaminants that accumulate in water as it sits in the pipes. Avoid using hot water from the tap. Lead and minerals leach into hot water more easily than into cold. Bacteria prefer warm water, too.