Is Distilled Water Sterile-Are They The Same Thing?

Distilled water is often seen as the gold standard for purity, but it is not sterile, and distilled water is not the same as sterile water. While the distillation removes minerals, chemicals, and many impurities, it doesn’t guarantee the absence of all microbial life. That’s where sterile water comes in.

Although they might seem similar, distilled water and sterile water serve different purposes, and knowing the difference is important, especially in medical, laboratory, or sensitive settings. 

In this article, we’ll break down how each type is processed, what they're used for, and why choosing the right one matters. You might be amazed by all the uses of each type, and all the things you can do with a good-quality water distiller.

Sterile Water vs. Distilled Water – How They're Made

The most significant difference between sterile water and distilled water lies in their production processes. While distillation removes impurities, it does not guarantee sterilization. 

• Sterile water, on the other hand, is always produced through a process that includes sterilization to eliminate all microbial life. 

• Simply put, all sterile water is distilled (or otherwise purified) and then sterilized, but not all distilled water has been sterilized.

Though both types of water are purified, the methods used to create them are quite different, and so are their typical uses.

Let’s begin by taking a closer look at how sterile water is made.

How Sterile Water Is Made

Sterile water typically begins as purified water, often produced through distillation, reverse osmosis, or deionization. These methods remove minerals, salts, and most contaminants. But to be classified as sterile, the water must undergo an additional step: sterilization.

There are several ways this can be done:

• Autoclaving: High-pressure steam is used to kill all forms of microbial life, including bacteria, viruses, and spores.
• Filtration: Water is passed through ultra-fine microbiological filters that physically remove microorganisms.
• Gamma Irradiation: High-energy gamma rays disrupt microbial DNA, effectively sterilizing the water.

Once sterilized, the water is carefully sealed in sterile conditions to prevent any recontamination, making it safe for medical, pharmaceutical, or laboratory use.

How Distilled Water Is Made

Distilled water is created through a process called distillation, which focuses on removing impurities by using heat and condensation.

Here’s how it works:

1. Boiling: Regular water is heated until it turns into steam. This leaves behind most minerals, salts, and contaminants that have higher boiling points.
2. Condensing: The steam rises and is collected in a separate chamber, where it cools and condenses back into liquid water.
3. Collection: The resulting water is now free from dissolved solids, many chemicals, and most impurities.

Distilled Water vs. Sterile Water: What Contaminants are Removed?

While distillation removes a wide range of contaminants, it does not guarantee sterility.

 Some heat-resistant microorganisms or airborne microbes could still be present if the process isn’t followed by sterilization or if the water is not handled in a sterile environment.

Distilled Water Removes:

• Minerals like calcium, magnesium, and sodium
• Heavy metals such as lead, mercury, and arsenic
• Organic compounds and some bacteria
• Sediment and dissolved solids
  

Distillation is highly effective at removing inorganic impurities and dissolved substances, making the water extremely pure from a chemical standpoint, but it doesn't necessarily eliminate all microbial life.

Sterile Water Removes:

• Bacteria
• Viruses
• Fungi and mold spores
• Any living microorganisms

Sterile water is treated specifically to eliminate all forms of microbial life, making it safe for medical or laboratory use.

If the sterile water has also been distilled (which it often is), it removes the same chemical and physical contaminants as distilled water, plus it’s microbe-free.

Distillation vs Sterilized Water: Contaminants Removed

Uses of Sterile Water vs. Distilled Water

Because sterile and distilled water are processed differently and remove different types of contaminants, they’re suited to different uses. 

Understanding when to use one over the other is essential, especially in medical or technical settings.

Common Uses of Sterile Water

Sterile water is required in environments where absolute microbial purity is critical. It is typically used in:

• Medical procedures – for wound irrigation, injections, and as a diluent for medications
• Hospitals and clinics – to mix infant formula safely in neonatal care
• Laboratories – to ensure sterile conditions in sensitive experiments
• Surgical settings – for rinsing instruments without introducing bacteria or spores

Because it’s free from all microbial life, sterile water is considered safe for direct contact with the human body.

Common Uses of Distilled Water

Distilled water is valued for its lack of minerals and chemical impurities, which makes it ideal for equipment and processes that require mineral-free water. It’s commonly used in:

• Steam irons – to prevent mineral buildup and extend appliance life
• CPAP machines – to avoid introducing minerals into the airway
• Car batteries and engine cooling systems – where minerals can damage components
• Aquariums – to control water chemistry more precisely
• Laboratory work – when purity is needed, but sterility is not critical
• Preparing baby formula at home – to avoid unwanted minerals in infant nutrition (though not sterile, it’s often preferred over tap water)

Comparison of Sterile Water and Distilled Water Uses

Some Notes to Keep in Mind:

• Distilled water can be used to mix baby formula at home if sterile water is not required, but boiled tap water is sometimes preferred depending on health guidelines.
• You can use distilled water for plants, but you must take proper precautions.
• Sterile water is not typically recommended for drinking or formula preparation unless specifically advised, as it may lack essential minerals and is not intended for routine consumption.

Use Sterile Water or Distilled Water?

When choosing between sterile water and distilled water, the right option depends entirely on how you plan to use it.

• Use sterile water if you're working in medical, surgical, or laboratory settings where water must be completely free from bacteria, viruses, and other microorganisms. 
• It’s the safest choice for wound care, injections, infant formula in hospitals, and rinsing surgical tools.
• Use distilled water if your goal is to avoid minerals and chemical contaminants. 
• It’s ideal for appliances like steam irons and CPAP machines, automotive batteries, aquariums, and even for mixing baby formula at home when sterile water isn’t required.

In short:

• Need it microbe-free? Go with sterile water.
• Need it mineral-free? Distilled water is your answer.
  

Always check the specific requirements of your intended use, especially for medical or infant-related purposes.

Distilled vs. Sterile Water: Cost, Storage, and Availability

• Distilled water is more convenient, available, and affordable for most people, especially in situations that don’t require 100% sterile water. Besides, it is easier to store for future use.
• Distilled water is much more affordable, and it is widely available at grocery stores. 
• It can also be stored for long periods in clean containers, even though it’s not indefinitely pure after opening.

Here's our popular guide that answers whether distilled water goes bad and provides detailed storage tips for distilled water.

Why is Sterile Water More Costly?

• The additional cost of sterilization and packaging makes sterile water more expensive than distilled water.  It also has a shorter shelf life once opened.
• It also needs to be stored in sterile and sealed containers to prevent recontamination. This can be too expensive and too demanding for many people.

Can You Use Sterile and Distilled Water as Substitutes?

In some specific applications, you can use sterile and distilled water as substitutes. However, you must only do so after taking proper precautions.

• For example, if you need water that won’t leave mineral buildup on your devices, you can use sterile water if it has gone through the process of distillation. If not, don’t use it.
•  Also, if you need water that’s sterile and contains no bacteria or other harmful microorganisms, using distilled water isn’t a good option. 

Here are some basic guidelines to follow when using both kinds of water as substitutes:

• In medical use, sterile water is necessary, and you can’t substitute it with distilled water
• For appliances or drinking, distilled water is good enough
• In emergencies, sterile water can be used in place of distilled water, but not the other way around, when you need sterility

Get a Water Distiller: Make Your Own Distilled Water

Distilled water is typically used more frequently, and if you know how to use a water distiller, you would find it quite easy to make distilled water at home. Investing in a quality water distiller is often the smarter choice. 

Now that you understand the key differences between sterile water and distilled water, let’s explore some water distillers that could be a great fit for your everyday needs. 

CO-Z 750W Countertop Water Distiller

This water distiller produces 0.3 gallons of clean water per hour with a 1.1-gallon capacity. It is made with food-grade materials, and it is also safe, easy to operate, and perfect for both home and commercial use, including appliances like CPAP machines and humidifiers.

CO-Z 4L Stainless Steel Water Distiller

This water distiller is made of a stainless steel chamber and coil, with BPA-free, food-grade plastic parts for top safety. Typically, it can distill up to 6 gallons per day, and it includes a premium glass carafe. As such, it offers a simple one-button operation with an automatic shut-off option.

Conclusion

So, is distilled water the same as sterile water? The short answer is no. The long answer is that both options have certain advantages and specific applications that make them very different. Keep in mind these differences when making your choice!

Here are some more guidelines on how to choose a water distiller for your home.