Should I Boil the Water When Preparing Baby Formula?

Red kettle
Greg Wohead/Flickr/CC By 2.0

When preparing baby formula it is important to mix it correctly with safe drinking water according to the directions on the formula's packaging. But you may question whether your tap water is safe and whether it should be boiled before using. The simple answer is that if you have any doubts, boil cold tap water for one minute and cool it before using it to mix baby formula.

Start With Cold Tap Water for Baby Formula

When using tap water for baby formula, always use cold tap water that has run for 15 to 20 seconds rather than warm or hot tap water. The reason for this is that many homes have plumbing with lead or lead solder and hot water can concentrate the lead, which is a risk factor for lead poisoning. Running the water to ensure a fresh flow and only using cold water can help reduce your baby's exposure to lead from tap water. Unless you have an inline hot water heater, your hot water has sat in a hot water tank and may have an increased level of lead. According to the U.S. Environmental Protection Agency, you should "never cook or mix baby formula using hot water from the tap." Boiling the water doesn't get rid of the lead. Many home water filters, including pitcher and faucet filters, do remove lead from drinking water, but it is best to start with a fresh flow of cold water.

Boiling Water for Baby Formula

The FDA recommends boiling cold tap water for one minute and then cooling it to body temperature before mixing baby formula. While most brands of baby formula once recommended boiling as a part of their instructions, they now often recommend "asking your baby's doctor or "local health department" instead. The American Academy of Pediatrics says simply to use safe water. They add that if you have any concerns about whether your tap water is safe to boil it for at least one minute and then use the boiled water within 30 minutes to mix the formula.

Sterile Water for Baby Formula

Purified, filtered, or bottled water, even the brand Nursery Purified Water, isn't sterile, so isn't necessarily any safer than unboiled tap water. Bottled and filtered water should have fewer impurities and contaminants, including lead, but could still have bacteria, which would be killed by boiling.

For those using tap water from public water supplies, there is little danger as the water supply is constantly monitored and warnings are issued if there is a risk of contamination. But because a young baby has a weaker immune system, the step of boiling tap water is one many parents take. 

Sterile liquid baby formula is recommended for infants in high-risk situations (if the babies aren't breastfeeding), especially for premature babies in the neonatal intensive care unit.

WHO Guidelines for Preparing Formula

The World Health Organization (WHO) issued guidelines for the safe preparation, storage, and handling of powdered infant formula after experts recognized that powdered formula was not sterile and was sometimes putting babies at risk for serious bacterial infections. Boiling water when preparing baby formula is very important in many parts of the world, especially developing countries that do not have safe water supplies.

To reduce this risk, the WHO recommends cleaning and sterilizing feeding and preparation equipment and then making a fresh bottle of powdered infant formula for each feed. Their recommendations are good ones in general for food safety. Use these steps:

  • Clean and disinfect all surfaces you will be using and wash your hands properly.
  • Boil water, even if it is bottled water
  • Let the water cool (not more than 30 minutes) and pour it into a cleaned and sterilized bottle.
  • Add the exact amount of powdered formula to the water.
  • Assemble the bottle and mix the powdered formula thoroughly.
  • Quickly cool the bottle by holding it under running tap water or by placing it in a container of cold water or iced water.
  • Dry the bottle with a clean cloth.
  • Check the temperature of the formula so that it doesn't burn your baby's mouth.
  • Feed your baby if the formula is at an appropriate temperature.

Baby Formula Safety

After you prepare your baby's formula, you should follow some simple rules to keep your baby safe.

  • Unless you refrigerated the prepared formula, feed it to your baby within two hours (hold time).
  • If you do put the prepared formula in the refrigerator, be sure to use it within 24 hours.
  • Once your baby starts feeding from a bottle, be sure he finishes the formula within one to two hours (hang time) and don't put the bottle back in the refrigerator. The unused formula should not be saved for later. Instead, simply prepare less formula next time so that you don't have so much left over.
  • Don't warm baby formula bottles in the microwave. Instead, use a baby bottle warmer or place the bottles in a container of warm water.
  • Follow the baby formula mixing instructions carefully and don't dilute or concentrate the baby formula unless your pediatrician tells you to.

Fluoride and Preparing Baby Formula

Experts often recommend that children should get fluoridated water to help prevent cavities. Surprisingly, infants who are fed powdered or concentrated liquid formula which is mixed with fluoridated water can get too much fluoride.

Getting too much fluoride when your child's teeth are still forming can lead to enamel fluorosis, which can cause tooth staining. This staining can appear as faint white markings on a child's baby teeth, and even more importantly, their permanent teeth.

Fortunately, fluorosis is usually very mild when it is caused by fluoridated water and baby formula and the staining is barely noticeable. To reduce your baby's chance of developing even mild fluorosis, it can help to use low-fluoride water (less than 0.7 mg/L) when you prepare your baby's formula, including some types of tap water, and water that has been purified, deionized, demineralized, distilled, or filtered by reverse osmosis.

You don't have to be concerned about fluorosis if you are exclusively or mostly breastfeeding your baby or using a ready-to-feed baby formula.

A Word From Verywell

As more and more adults have switched to bottled water rather than tap water, it is natural to have concerns about using tap water for infant formula. Talk to your pediatrician to see if you need to boil your water, especially if you are using well water that hasn't been recently tested, or if you aren't convinced that the tap water where you live is safe and healthy for a baby.

Was this page helpful?
View Article Sources