Is Hard Water Residue Safe on Baby Bottles? [Prevention & Cleaning Tips]

Balint Horvath, PhD

Writer, parent, and veteran of baby feeding battles.


While cleaning my little one’s baby bottles, I noticed a few unusual white stains on some bottles. I found this quite concerning and did some research on the possible causes. One common cause appeared to be hard water stains. This left me wondering whether hard water residue on baby bottles is safe. I also found a few tips to effectively deal with hard water around your baby bottles.

Hard water residue on baby bottles can be harmful to newborn babies since they don’t have a strong immune system. Hard water can leave residual layers of salts and mineral buildup in the bottle, cleaning components and even sterilizers. 

Key takeaways

  • Hard water is made up of excess calcium and magnesium build-up in tap water
  • If the calcium and magnesium build-up in the water is too high it can be harmful
  • Vinegar is the top way to remove hard water residue from bottles and accessories
  • Adding a water softener and tap filters are effective ways to soften water

What is hard water residue on baby bottles?

Hard water residue comes from water that contains high levels of calcium carbonate which is essentially just magnesium and calcium. Typically, hard water is formed when water flows over rocks and gathers up these minerals. Using this water to wash your bottles may cause these salts to remain on the bottles. 

Is hard water residue on baby bottles harmful?

For the most part, hard water isn’t all that harmful to drink, if the calcium levels are under .07mg/L. Any levels higher than this can be harmful. Furthermore, if the minerals in the water are strong enough to leave residue on the bottle, they may cause skin irritations during bathing. 

How to get hard water residue off of baby bottles

Consider the following two methods to wash hard water residue off your baby bottles. 

Soak bottles in water and vinegar

I’ve found that vinegar is one of the top ways to remove hard water residue from your baby bottles. This is because vinegar’s acidic properties are highly effective at breaking down minerals and serves as an antibacterial agent to clean just about anything. You can use vinegar to clean the bottles, accessories, and bottle parts as well as the sterilizing unit. 

Use cold water and soap to wash bottles

Another way to reduce the effects of hard water is to wash the bottles with cold water and soap. Be sure to sterilize your bottles a few times a week to ensure they remain bacteria-free. 

How to prevent hard water residue on baby bottles 

There’s some good news though. In my search for the best ways to prevent hard water residue on your baby bottles, I’ve found some effective recommendations. 

Consider using still-bottled water to clean baby bottles

Many parents I spoke to in the area simply resort to buying large quantities of still-bottled water that’s used specifically for anything baby related. That includes washing bottles, utensils and accessories. Well water is something you should avoid as I wrote about in the article on if you can wash baby botltes with well water. That type of water has minerals which lead to visible residues.

Put a filter on your taps

A tap filter is a device that easily improves the quality of tap water. I found that installing these filters is quick and easy and one of the more cost-effective, long-term solutions. 

Use a water softener in your water system

Another very effective way to reduce the effects of hard water is by installing a home water softener into your water system. Also referred to as ion exchange units, these gadgets work in the water system by removing magnesium and calcium from the water. This makes the water softer and better for drinking, washing bottles and even bathing. 

How to disinfect baby bottles with hard water stains

As I mentioned earlier, vinegar is a wonderful antibacterial. The best way to rid your bottles of hard water stains and residue is by soaking them in vinegar for a thorough clean. Here’s how. 

  • Step 1: Pour 1 cup (250 ml) of white vinegar into a container of boiling water (or into your sterilizing unit)
  • Step 2: Leave for a period varying between 30 minutes and 24 hours, depending on the level of residue
  • Step 3: Rinse the bottles with cold, distilled water
  • Step 4: Repeat if necessary

Here’s a quick clip that highlights how to clean a bottle sterilizer with vinegar and this is an article I wrote about using vinegar.

Other reasons for white residue on baby bottles

  • Heat and chemical stress caused by washing bottles in high temperatures – read about it in my article about reasons why bottles turn cloudy
  • Scratches on the inside of the bottle caused by excessive cleaning from the bottle brush
  • Stains caused by milk fat and proteins which easily cling to plastic


Calcium and magnesium buildup could have a few negative effects on your baby. With the tips provided, I hope you’ll be able to reduce your baby’s exposure to hard water. 

My article about drying baby bottles is quite useful when you’re cleaning your bottles. Additionally, understanding a few more reasons why baby bottles look greasy makes it easier to keep your bottles clean and healthy!

Photo of author


I’m Balint, founder of this site and a father (and dad) to a baby-turned toddler. I found the world of babies so fascinating that I started a blog dedicated only to that topic. By the way, I studied physics, engineering (PhD, MSc), and therefore I do a thorough research when I write about something. Since it’s a blog, of course I also write about my personal experiences.

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