Can You Use Reverse Osmosis Water for Baby Formula?

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There is a lot of conflicting information online about what kind of water to use for baby formula.

Some say reverse osmosis water is the best, and others say it shouldn’t be used at all. No wonder people are confused.

Let’s discuss!

Key Takeaways

  • For the most part, you can use your reverse osmosis water to mix baby formula. However, some regulatory bodies may suggest boiling it to be safe.


Before we dive into whether or not RO water is appropriate for making baby formula, let’s see what the regulatory bodies have to say about their guidelines for preparing baby formula.

  • The World Health Organization (WHO): This international body states that all water used to make baby formula should be sterilized (boiled), whether tap or bottled and added to the formula before the temperature drops below 70 °C.
  • The Food and Drug Administration (FDA): The FDA states that tap, bottled, or RO water needs to be boiled before use and that any ‘safe’ water is okay for baby formula. ‘Safe’ water is that which meets the EPA guidelines. The EPA guidelines for safe water set legal limitations on over 90 contaminants and can be found here.
  • Centers for Disease Control and Prevention (CDC): The CDC says it’s okay to use water with fluoride in it for making baby formula. But, if your baby only drinks formula made with this kind of water, they might have a slight chance of getting minor tooth fluorosis. To lessen this risk, you can sometimes use bottled water that has low fluoride for the formula. This kind of water is known as de-ionized, purified, demineralized, or distilled, and it doesn’t have any extra fluoride put in it after it’s been cleaned. If there is any added fluoride, the FDA requires it to be shown on the label.

bottle with baby formula

Can You Use Reverse Osmosis Water for Baby Formula? Is It Safe?

So, can you use reverse osmosis water for baby formula? Yes, you can use reverse osmosis water for baby formula, based on the information above.

Using reverse osmosis water for baby formula is safe. However, the World Health Organization recommends boiling the water used for making formula, regardless of its origin, as a precautionary measure.

Adding minerals back into your reverse osmosis water will also improve the taste and restore essential minerals like calcium, magnesium, and potassium, that your baby could benefit from, though the regulatory bodies do not mention whether this is necessary.

In the United States, many pediatricians might even suggest that boiling water isn’t necessary as long as the water comes from a ‘safe’ source. A well-kept RO system is undoubtedly a ‘safe’ water source, but it’s always wise to confirm with your specific pediatrician.

Benefits: Why to Use RO Water for Baby Formula

There are several reasons why using RO water for your baby formula could be of benefit.

Free from Lead and Other Harmful Contaminants

The process of reverse osmosis filtration removes lead, chromium 6, and other harmful contaminants that could be toxic to a child even in low doses.

No or Low Sodium Content

Sodium, in regulated quantities, is beneficial for children’s growth and development. However, if you reside in an area with hard water, your water likely contains high sodium levels, which may pose a risk to your baby’s kidneys, as they are not well-equipped to process sodium.

No or Low Fluoride Content

The topic of fluoride consumption in infants has sparked discussions among health organizations. Too much fluoride in water can be detrimental to bone and dental health. As most infant formulas already contain the necessary amount of fluoride, so it’s preferable to use water that is either free of fluoride or contains very low levels.

The semi-permeable membrane in a reverse osmosis system effectively removes fluoride from tap water, allowing you to control the fluoride content your baby consumes.

How Fluoride Exposure Can Affect Babies

Fluoride is known to be toxic when ingested in very large quantities. Excess fluoride can interfere with the development of your baby’s bones and teeth, leading to potential discoloration, deformities, or even dental fluorosis.

Breastfed infants may be exposed to fluoride through their mother’s diet if she consumes fluoridated tap water or other foods and drinks with high fluoride levels. Therefore, it’s essential to be aware of the sources of fluoride, both inside and outside your home.

Free from Microorganisms (No Need for Boiling)

Historically, manufacturers’ advice was to boil any water intended for use in baby formula. However, the current recommendation is often to seek advice from your pediatrician.

The American Academy of Pediatrics emphasizes the importance of using water from a safe source. They also note that if you’re confident in the safety of your tap water, you can mix it with formula at room temperature without the need for boiling or sterilization.

Due to its filtration process, reverse osmosis water has no microorganisms. With RO water, you can be confident that your baby’s formula is free from contaminants. While the World Health Organization still advises boiling any water used for baby formula, this is an extra cautionary step to ensure any pathogens potentially introduced between the water purification process and the formula preparation are eliminated. It also considers that some people may not properly maintain their RO system or test their water and cannot guarantee its complete safety.

Cheaper Than Bottled Water

Contemplating bottled water for your baby’s formula requirements might lead you to rethink due to its high cost. You can have safe water with a reverse osmosis system. Once installed, it provides your baby and your entire family access to purified drinking water at a fraction of the cost.


Reverse osmosis systems are engineered to eliminate as much as 98% of pollutants and total dissolved solids from water. The resultant RO water lacks many vital minerals necessary for human health.

However, some reverse osmosis systems come equipped with a remineralization filter, or you can often add one on! This filter reintroduces essential minerals to the water before it’s dispensed from your tap.

Tips for Using Reverse Osmosis Water for Baby Formula

Here are some handy tips when using RO water when preparing baby formula:

  1. Start with a clean, sterilized bottle.
  2. Pour RO water into the bottle, following the correct measurements.
  3. Heat the water until it boils to ensure any microbes in the formula are eliminated.
  4. Add the baby formula to the water.
  5. Always remember to add the water before the formula.
  6. Shake the bottle thoroughly before feeding your baby.
  7. Dispose of any remaining formula, as it can harbor bacteria over time.

Under Sink Reverse Osmosis System

How About Using Other Types of Water for Preparing Baby Formula?

You can use other types of water for your baby formula, as long as it is from a ‘safe’ source.

Tap Water

Like all water sources, including those used by bottled water companies, city water supplies can be exposed to environmental contamination. To lessen these contaminants and enhance the water’s quality, it is filtered and disinfected at water treatment facilities.

City water is treated with chlorine (or chloramine) to kill harmful microbes. But, chlorine can react with organic matter naturally found in water to create toxic byproducts such as trihalomethanes. Additionally, some city water supplies include fluoride in the water, which is seen as beneficial by some and harmful by others.

Another concern is lead contamination, which can occur after the water has left the treatment plant. Lead, a toxic metal, can pose long-term health risks, particularly for infants and young children. This is primarily a concern in older homes with lead pipes.

So, while tap water can be used, it needs to be considered safe as per the EPA guidelines.

Bottled Water

Certain sources suggest avoiding the use of bottled water for preparing baby formula. The NHS cautions that bottled water may not be sterile and could contain high levels of salt or sulfate, making it unsuitable for baby formula preparation. Additionally, over 90% of bottled waters worldwide contain microplastics.

On the other hand, the CDC and other organizations state that bottled water can be used to mix powdered or liquid concentrate infant formulas. However, parents should note that the fluoride content in bottled water can vary. To reduce this risk, parents might use low-fluoride bottled water labeled as deionized, purified, demineralized, or distilled for mixing baby formula. These types of bottled water do not have any added fluoride post-purification.

Some bottled water brands market their product specifically for infants or for mixing with formula. Water labeled for infant use must meet EPA standards for tap water and indicate that it is sterile.

Softened Water

You should not use artificially softened water when mixing baby formula. For those with a domestic water softener system, always mix your infant’s formula feeds with water from a tap not connected to the softener (there is typically at least one such tap in every house), or use filtered water if you have a water purifier.

Why? Softened water has increased sodium levels.

Distilled Water

Water distillers operate by heating water to a boiling point and converting the steam into purified water. Most of these systems also include a carbon post-filtration stage. Water distillation eliminates nearly all impurities, such as microorganisms, lead, organic compounds, and pesticides.

When used with a carbon filter, distillation is the most powerful method of treating water at home. However, this comes with a high initial cost and operational expenses due to significant electricity consumption. However, they are safe to use for preparing infant formula.

Well Water

Water originating from certain private wells may not be suitable for consumption by babies and expectant mothers. Water from shallow wells can potentially contain residues from agricultural fertilizers, such as nitrates, lead, arsenic, and selenium. High nitrate concentrations in drinking water can impair a baby’s blood oxygen-carrying capacity, leading to a severe condition known as methemoglobinemia.

If your water source is a spring or well that doesn’t employ chlorine, you are at a heightened risk of microbial contamination. Well water needs to be regularly tested and maintained, and it is risky to use it to make infant formula, particularly without boiling it first.

If you have any thoughts about the question, is reverse osmosis water safe for baby formula, please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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