What to Know About Water for Baby Formula

Medically Reviewed by Renee A. Alli, MD on July 08, 2023
4 min read

The market for bottled water across the globe is increasing daily, and younger people seem to be its best customers. Yet when it comes to choosing water to use in baby formula, ordinary water not bottled water may be the healthier choice. Some natural mineral waters are not healthy for babies due to the number of minerals they contain. 

You can start giving your baby bottled water after six months, though. Mineral water for babies is fine as long as the level of dissolved minerals (such as sodium and fluoride) in it are low.   

The key thing to remember is that you should boil water that you’ve collected from a safe source when you mix infant formula. Cool water to room temperature before using it.

Bottled water. If you have to use bottled water because no other clean water is available to you, you may want to check out bottled water that’s labeled specifically for babies. However, since bottled water is not usually sterile, it is good to take precautions like boiling it and letting it cool before using it to make your baby's formula.  

Tap water. In most places, tap water will be safe for you and your baby. However, it’s still important to boil it before mixing it with your baby’s formula. 

Well water. Well water can easily get contaminated with toxic substances from the dirt, plants, or water around it. For this reason, if well water is not tested or known to be safe, avoid using it to make your baby’s formula. 

Most wells have nitrates in amounts that are over federal drinking water standards. Nitrates are made of plant matter and ingredients in fertilizers that get into well water. 

They carry no risk to humans until we drink the water. Then they mix with our body chemistry and can turn poisonous. 

It is important to get well water tested for nitrates and to make sure it is also free of:

  • Copper
  • Mercury
  • Bacteria
  • Viruses
  • Lead
  • Aluminum
  • Selenium
  • Ammonia

If you prepare your baby’s formula with unsafe well water, you put them at risk of a condition called methemoglobinemia, or "blue baby disorder."  This is a blood disorder that interferes with oxygen circulation in the blood and can be fatal.

A note about fluoride. Fluoride is a naturally occurring mineral that can be found in drinking water. It is also added to toothpaste and mouth rinse to protect your teeth from cavities. 

Fluoride helps prevent tooth decay by rebuilding the outer coating (enamel) of teeth when acids from sugar damage it. But too much fluoride from toothpaste, drinking water, or water used to prepare infant formula may cause dental fluorosis in your child. It often shows up as faint white lines on their teeth.

According to the World Health Organization, when there is more than 1.5 milligram of fluoride per liter of water, the risk of developing fluorosis is high. And medical professionals vary on their level of concern about fluorosis.

The American Academy of Pediatrics, for example, notes that your child's risk for fluorosis is over once their adult teeth start coming in. Yet there are also studies that link fluorosis to behaviors that suggest ADHD and lower IQ in children. 

When choosing low-fluoride bottled water, it’s important that you check the label and go for water that’s labeled purified, deionized, demineralized, or distilled. This means that some amount of fluoride has been removed from the water so that it won't be harmful to your baby.

When to boil water. The American Academy of Pediatrics advises you to use water from a safe source to prepare infant formula or boil the water every time you are preparing your baby’s formula. This is to keep your baby away from infections caused by bacteria, viruses, or other germs carried by the water.

If your baby is six months and below, always boil water and let it cool down before using it to prepare their formula. But do not boil it for more than one minute. That way, you'll prevent additional impurities from getting into the water. 

For babies more than six months old, boiling tap water is not necessary. Boiling tap water doesn’t change the amount of fluoride in it. In fact, boiling can increase the concentration of fluoride in water. 

If you are concerned about how much fluoride your baby consumes, you can use low-fluoride bottled water to make your baby’s formula. 

When preparing your baby’s formula, whether with bottled water, tap water, or well water, always ensure that it is totally safe for consumption. If you're not sure, always make a point of boiling it. This will lessen your baby's risks of consuming harmful germs that may shake their health.