Should I Boil the Water When Preparing Baby Formula?

Red kettle
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Since few babies like cold baby formula and you do usually have that extra step of warming the formula after you make it, using warm or hot water to start with from the tap does seem like it could save an extra step. You should never do it, though.

Preparing Baby Formula

Instead, follow the directions on your baby's formula package and if using tap water, start with cold tap water. According to the U.S. Environmental Protection Agency, you should "never cook or mix baby formula using hot water from the tap."

What's wrong with hot tap water? Many homes have plumbing with lead or lead solder and hot water can concentrate the lead, a risk factor for lead poisoning. Running the water for 15 to 30 seconds and only using cold water can help reduce your baby's exposure to lead from tap water.

Boiling the water doesn't get rid of the lead either. Many home water filters, including pitcher and faucet filters, do remove lead from drinking water, though.

Boiling Water for Baby Formula

Another common question about preparing baby formula is whether or not you have to boil the water first. 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 doesn't offer any formal advice on the subject either. The latest book on newborns that they published, Heading Home with Your Newborn: From Birth to Reality, does say that "you may want to use boiled or purified (bottled or filtered) water, at least in the first month or two."

Sterile Water for Baby Formula

The main problem with that statement is that purified, filtered, or bottled water, even the brand Nursery Purified Water, isn't sterile, so isn't necessarily any safer than tap water that hasn't been boiled first. Bottled and filtered water should have fewer impurities and contaminants, including lead, but could still have harmful bacteria, which was the whole reason you were supposed to boil tap water when making a baby formula in the first place.

And there is no research which states that doing anything special to the water that you use for your baby's formula "in the first month or two" is helpful or does anything at all. That advice is likely based on the fact that younger babies are simply supposed to have weaker immune systems.

If you do decide to boil the water when preparing your baby's formula, the FDA recommends that you "bring it to a very bubbly boil. Keep boiling it for a minute or two, then let it cool." Once it has cooled, you will be ready to add it to your baby's formula.

WHO Guidelines for Preparing Formula

The World Health Organization 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.

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 by:

  • Cleaning and disinfecting all surfaces you will be using and washing your hands properly
  • Boiling water, even if it is bottled water
  • Let the water cool (not more than 30 minutes, though, so it doesn't get below 70 degrees) 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

The WHO also offers detailed advice on storing extra formula and traveling with prepared formula.

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.

What You Need To Know About Water and Baby Formula

In addition to not using hot water from the tap, other things to know about preparing baby formula to include that:

  • Powdered baby formula is not sterile and there have been cases of Salmonella and Cronobacter sakazakii infections linked to powdered infant formula.
  • 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.
  • Sterile liquid baby formula is recommended for infants in high-risk situations, if the babies aren't breastfeeding, especially for premature babies in the NICU.

And most importantly, 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. Your pediatrician can also recommend water -- tap, filtered tap, or bottled water -- that is best for mixing your baby's formula.


American Academy Of Pediatrics. Heading Home with Your Newborn: From Birth to Reality (Paperback). by Laura A. Jana, Jennifer Shu

Brouard C. Two consecutive large outbreaks of Salmonella enterica serotype Agona infections in infants linked to the consumption of powdered infant formula. Pediatr Infect Dis J - 01-FEB-2007; 26(2): 148-52

CDC. Community Water Fluoridation. Background: Infant Formula and the Risk for Enamel Fluorosis

Mimouni FB. Bacterial contamination during routine formula preparation. - Am J Infect Control - 01-FEB-2002; 30(1): 44-5

U.S. EPA. Is There Lead in my Drinking Water? .

U.S. Food and Drug Administration. Feeding Your Baby with Breast Milk or Formula

WHO. Guidelines for the safe preparation, storage, and handling of powdered infant formula. Accessed Dec. 2011.