Formula Preparation: What Type of Water Should I Use?

pouring water into a baby bottle in a kitchen

Read time: 5 minutes

What should I know about the water used for preparing formula:

  • Find out if your tap water is safe to prepare infant formula, or if a different type of water should be used
  • Understand if boiling water to prepare infant formula is necessary

When it comes to preparing formula, one of the most confusing parts has to do with the water you use. What type can you use? Do you have to boil it? A lot of the answers depend on your baby, your family’s preferences, and even the area you live in. 

Read on to get all your formula-water questions answered.

What type of water should I use to prepare infant formula?
City or town water

If your city or town has safe drinking water with low levels of contaminants such as lead, then it is usually safe to use cold drinking water to make formula.1, 2 However, if you live in an older house with lead pipes, ask your baby’s pediatrician what the best course of action is.

Well water

Should you live in a place that uses well water, it’s important to have it tested for nitrates before using it for formula. Nitrates naturally occur in plants and nitrate-containing fertilizers, and are usually not toxic.3 The problem is that the body converts nitrates to nitrites, which in high amounts may be dangerous for babies.4

If tests show high nitrate amounts in the well water, it may be important to use bottled, town/city water, or nursery water to prepare food and formula for your little one.3

Bottled water

Some bottled waters are just tap (municipal) water.9 Just like municipal tap water, bottled tap water must be treated, though it’s important to note that it may contain fluoride. To know if the bottled water you choose is tap water or from another source (Well, spring, or mineral water), look for these statements on the bottle: “From a community water system,” or “from a municipal source.”10

Fluoridated water

Most cities and towns add fluoride to the water. This is great for baby’s growing teeth.5 However, formulas also contain fluoride, and this may lead to a slightly increased risk for milk fluorosis, or white markings on their teeth.6

Since all formulas contain a low amount of fluoride, mixing fluoridated water with formula could cause mild dental fluorosis.6

Distilled water, purified water, de-mineralized, or de-ionized water are typically lower in fluoride and may be less likely to cause fluorosis.6

Speak with your pediatrician should you have a concern about the type of water you need to use for preparing infant formula.                             

For more information about fluorosis from the CDC: https://www.cdc.gov/fluoridation/faqs/infant-formula.html

Do I need to boil water to prepare infant formula?

It’s important to note that powdered infant formula is not sterile; there is a small chance that it may contain a rare but dangerous bacteria called cronobacter.7, 8 Because of this, some organizations like the World Health Organization (WHO) and Centers for Disease Control (CDC) recommend considering using additional precautions when providing powdered formula to infants who are at higher risk for infection, born prematurely, and/or who are younger than 3 months old.7, 8

Choosing liquid formula, or using boiled water to prepare powdered formula, may be safer in these situations.

When you do not need to use boiling water to prepare formula

Babies who are full-term, over 3 months old, and do NOT have weakened immune systems can use powdered formula without boiling water. 7, 8

Speak with your baby’s pediatrician if you are concerned and would like to discuss which type of formula, or method of formula preparation, may meet your little one’s needs best.

Read more: Does Your Baby Need a Sensitive Formula?

Using boiled water to prepare powdered infant formula

If your little one is a newborn and/or at higher risk of infection, your pediatrician may recommend boiling water to prepare powdered formula more safely. Boiling water and then adding powder to it while it is still hot will help kill cronobacter and other germs.7, 8  Should you use this method, be careful not to scald yourself when handling the hot water!

Here’s how to prepare powdered formula using boiled water:

  • Boil water from a safe source. Let the water come to a rolling boil.
  • Allow the water cool to no less than 158 degrees F (70 degrees C) before pouring into the bottle. Cooling the water slightly prevents the formula from clumping as well as destroying delicate nutrients like Vitamin C.
  • Carefully pour the water into the bottle you will use to feed baby.
  • Add powdered formula to this heated water, cover with a lid, and carefully shake to mix.7, 8

If you plan to use the formula right away, cool it by running under cold water or placing in an ice water bath until the formula is at body temperature. Always test the temperature by placing a few drops on your wrist before giving it to your little one.

If you will be using it later, place the capped bottle in the refrigerator until your little one needs it.

Read more: Everything You Need to Know About How to Prepare and Store Infant Formula

For more information

To read more on cronobacter and boiling water instructions, see the WHO’s formula preparation brochure at https://www.who.int/foodsafety/publications/micro/pif_guidelines.pdf  

or the CDC’s instructions at https://www.cdc.gov/cronobacter/prevention.html

Still uncertain? Call the pediatrician

If you are unsure what type of water to use while preparing formula, or if you should be boiling water or not – give the pediatrician a call. They know your baby best and can help you figure out the best way to prepare formula.

Let’s Chat!

We know parenting often means sleepless nights, stressful days, and countless questions and confusion, and we want to support you in your feeding journey and beyond.

Our Happy Baby Experts are a team of lactation consultants and registered dietitian nutritionists certified in infant and maternal nutrition – and they’re all moms, too! They’re here to offer personalized support on our free, one-on-one, live chat platform Monday – Friday 8am-8pm (EST), and Saturday – Sunday 8am-4pm (EST). No appointment needed, no email or sign-up required. Chat Now!

Read more about the experts that help write our content!

For more on this topic, check out the following articles:

Breast to Bottle: How To Transition

Feeding Tips for Healthy Weight Gain in Babies and Toddlers

What Do I Need to Know About Supplementing with Formula, Breastfeeding, and Pumping?

Should I Feed My Baby On Demand or On a Schedule?

Should I Switch Baby Formulas?

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