What Kind Of Water Is Safe For Mixing Formula Powder For My Baby?

Written By: Jody Segrave-Daly, MS, RN, IBCLC

Great question! Educational resources that parents have access to often give them mixed messages about safe formula preparation.  To answer the many questions we receive, we developed an up-to-date evidence-based resource guide for parents about safe formula feeding. We start with water sources available to parents in the United States, specifically. 

Public Water

The United States has one of the safest public drinking water facilities in the world, and it is strictly regulated by the Environmental Protection Agency known as the EPA. Your community’s public water system is routinely tested for safe consumption. The EPA sets legal limits on over 90 contaminants in drinking water. The Environmental Protection Agency’s Safe Drinking Water Hotline is  1-800-426-4791.

Private Well Water

It is estimated that more than 13 million households rely on private wells for drinking water in the United States. According to the EPA, private well owners are responsible for the safety of their water. This website educates well owners on wells, groundwater, and information on protecting their health.  

Testing your well water

The EPA recommends testing your private well annually to check for total coliform bacteria, nitrates, total dissolved solids, and pH levels. Guidelines on collecting your well water are here.

The American Academy of Pediatrics (AAP) recommends getting your well water tested for nitrates. If the well water contains nitrates (above a level of 10 mg/L), it should not be used for infant formula or food preparation. In infants, excessive nitrates can lead to a condition called methemoglobinemia, a dangerous disorder that interferes with the circulation of oxygen in the blood.

Dr. Sarah Zate, a pediatrician I interviewed for this resource guide, says “I ask [parents] if they’ve ever had their well water tested for water quality. If the answer is no, I recommend they get it tested, even if they don’t plan to make formula with the water, because of bathing their baby.” 

Testing  your household plumbing 

Since your house has its own water pipe system that transports water to your faucet, it can be a source of contamination for lead and copper.  According to the EPALead pipes are more likely to be found in older cities and homes built before 1986. Among homes without lead service lines, the most common problem is with brass or chrome-plated brass faucets and plumbing with lead solder.”

For more information about sources of lead in drinking water and testing click here.


Tips for water consumption from the AAP:
  • Use cold water for cooking and drinking. Contaminants can accumulate in hot water heaters.
  • If you are concerned about the quality of your plumbing, run the faucet for two minutes each morning prior to using the water for cooking or drinking. This will flush the pipes and lower the likelihood that contaminants will end up in the water you consume.
  • Have well water tested for nitrates before giving it to infants under one year of age.

Drinking water that may be contaminated with germs should be boiled and then allowed to cool before drinking. Boil for no more than one minute. However, it is important to remember that boiling water only kills bacteria and other germs; it does not remove toxic chemicals. If you don’t like the taste or smell of your tap water, filters made with activated carbon will remove the off-taste or smell. Such filters will also remove undesirable chemicals without removing the fluoride that prevents tooth decay.   

Where to test your water

Only use laboratories that are certified to do drinking water testing. To find a certified laboratory in your state, you can contact:

Dr. Zate recommends talking to your pediatrician, as water testing can cost $200, and the AAP recommends testing every 3 months.


Public drinking water may contain fluoride because of its protective factors against dental decay.  However, most formula powder already contains fluoride. If you are also using fluoridated water, it can be too much, causing your baby’s developing permanent teeth to have white spots. This is a condition called fluorosis. To find out if your tap water contains fluoride use this CDC tool.

Fluorosis Facts: Information Parents & Caregivers

Source AAP Healthy Children

Finding out how much fluoride is in your water is important to see if it has compatible levels with the formula you are using. According to the American Dental Association, the acceptable level of fluoride is less than 0.7 mg/L. Data & Statistics | Community Water Fluoridation | Division of Oral Health

What about fluoride in well water?

The fluoride level in your well water can be included when checking for total coliform bacteria, nitrates, total dissolved solids, and pH levels. For more information, the CDC offers detailed answers to your questions. Private Wells | Community Water Fluoridation FAQs | Community Water Fluoridation | Division of Oral Health The best thing to do when figuring out your baby’s fluoride needs is to talk to your pediatrician, as they will know your local demographics and can advise you accordingly.

 Dr. Zate explains, “I had three kids in three different regions with totally different fluoride situations, so we did [things] differently for each one. It’s a very local thing.

“Our water here doesn’t have added fluoride because the natural level is high enough. But [it’s] not so high that we see fluorosis, even with formula. So I usually leave it alone until their first dental appointment.”

Bottled Water

There are several types of bottled water to use when mixing formula.

  • The bottled waters that you can use are labeled as deionized, purified, demineralized, or distilled and are without any fluoride added after purification treatment (the FDA requires the label to indicate when fluoride is added). 
  • Some water companies make available bottled waters marketed for infants for the purpose of mixing with formula. 
  • The label must also indicate that the bottled water is not sterile, just like your tap water is not sterile.
  • For more information, see the FDA’s general Q&A about bottled water and infant formula.

For additional infant feeding education:

Do Parents Need To Boil Water For Powdered Infant Formula Preparation in the United States?

Safe Infant Feeding and Maternal Mental Health

Breastfeeding Plan:

How To Prepare For Supplementing When Breastfeeding Your Baby In The Hospital

For breastfeeding, formula feeding, pumping, combo-feeding, or tube feeding consults:


To join our parent support group:

  • If you need infant feeding support, we have a private support group– Join us here.


Dear Chrissy Teigen, You Are Right; We Need To Destigmatize Formula Feeding Our Babies



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