Filtered vs. Distilled vs. Purified Water

It’s easy to think that all water is the same, even if it looks or tastes a little different. However, that’s not the case — particularly when it comes to filtered vs. distilled vs. purified water. Here’s a quick look:

• Filtered Water: Filtration physically or chemically reduces the presence of certain water contaminants to improve taste, odor, appearance and overall safety.
• Distilled Water: Distillation uses evaporation to form steam; some water contaminants don’t evaporate and are left behind.
• Purified Water: Water purification is a blanket term for many kinds of water treatment, including filtration and disinfection.

It’s true that these water types are similar — so which one is best for drinking? What should you do with the others? Can you filter, distill or purify water at home?

Here’s everything you need to know.

Distilled Water vs. Purified Water

To understand what you should grab at the grocery store — or what kind of water treatment system you’d like in your home — it’s important to know all the different kinds of water.

Distilled Water

If you’re drinking distilled water, you’re taking a sip of something that used to be steam. The distillation process involves boiling water, which causes it to shift into its gaseous state — or steam. Along the way, many impurities are left behind because they don’t evaporate.

The reduced mineral content may cause distilled water to taste different. Still, it’s generally safe to drink — so while some people prefer other methods of removing contaminants from drinking water, there are plenty of options for getting distilled water when and where you need it.

Purified Water

Pure water doesn’t really exist in nature; even the freshest spring water can contain minerals and debris that may or may not be visible. As such, it’s important to note that water purification doesn’t technically make water “pure” — pure water is more of a general term for the water that remains after some sort of filtration, distillation or other purification process.

These processes are intended to remove a broad variety of substances you don’t want in your water, including harmful chemicals, inorganic minerals and organic materials.* They include methods such as disinfection, filtration, sedimentation, coagulation and flocculation. The outcome depends on the specific treatment process, but the idea is that purified water is generally safer to drink than untreated water. In some places, water must meet certain standards to be considered purified at all; for example, in the U.S., it must not contain more than 10 parts per million of total dissolved solids.

Keep in mind that “purified water” isn’t the best descriptor. While technically correct, the term doesn’t give you much information about how the water was treated. As such, if you see water branded as purified, it’s smart to take a closer look so you know exactly what kind of water you’re drinking.

Distilled Water vs. Filtered Water

Although they’re both used to improve water quality, distilled water and filtered water are not the same. The key difference is in how they’re treated — and what they’re best used for.

Filtered Water

Filtered water is treated using one or more filtration processes, such as activated carbon or reverse osmosis, to reduce or remove specific contaminants. These systems are often installed in homes to improve taste, reduce odors and address health-related concerns like nitrates, lead or PFAS. Because filtration systems can be tailored to different water issues, they’re a practical choice for daily drinking, cooking and cleaning.

While the distilling process does remove many impurities, including some chemicals and the hardness-causing calcium and magnesium, it doesn’t always remove chlorine or volatile organic compounds (VOCs), which evaporate at or below water’s boiling point — unless paired with an additional carbon filter.

Filtered Water or Bottled Water?

Not all bottled water is the same. When buying single-use bottled water, it’s important to look at the label. Some simply use treated municipal drinking water, while other brands may get their water from a source such as spring water. Many brands will also vary in the method of filtration used. Some options, including larger-format bottles, may be distilled instead of filtered.

Added Minerals in Filtered Water

In some cases, water filters might remove some of the mineral content you’ve gotten used to tasting. Fortunately, some systems have optional cartridges that can add minerals back to your filtered water. You can also buy mineral water, or spring water, which may be created using distillation instead of filtration.

Home Filtration Systems

A water distiller may be an unrealistic choice for your home, but filtration can be a simple solution that is well suited for drinking and cooking. The most best options for home filtration systems are:

• Reverse osmosis filtration system: These systems create RO water, which has been sent through a tightly woven membrane to address impurities that impact taste, odor, appearance and overall water quality.
• Whole home filtration system: These systems targeted specific water problems like iron, sulfur, chlorine and more that impact cleaning and bathing as well as drinking water

The ideal home filtration solution depends on your needs. That’s why it’s best to start with a professional water test, which can tell you all about water quality problems ,their causes, and what filtration system will work best in your home.

The Right Water for The Right Need

Filtered water isn’t always the only choice. How do you know when to use the other types?

Distilled Water Uses

While perhaps not the tastiest solution, distillation does create clean water for certain purposes, including continuous positive airway pressure (CPAP) devices, humidifiers, aquariums and car cooling systems. If you have these or other needs, look for water providers that offer distilled water delivery services.

Purified Water Uses

Remember that purified water is just another name for water that has been treated one way or another. It’s not the same as distilled water, but it has plenty of roles to play in your home. On top of that, highly purified water is sometimes even used for certain pharmaceutical applications and laboratory tests.

Filtered Water Uses

You can use filtered water for just about anything, from drinking and cooking to cleaning and bathing. However, if you notice other water issues — such as soap scum, mineral buildup, stiff laundry and spotty dishes — you may want to consider water softening in addition to filtration, as hard water isn’t addressed by reverse osmosis or other filtering methods.

FAQs About Distilled and Purified Water

 

Is Boiled Water the Same as Distilled Water?

Not quite. Boiling water kills bacteria and other microorganisms, but it doesn’t remove hard minerals like calcium and magnesium, nor does it remove chemical contaminants. In contrast, distilled water is created through boiling and re-condensing, which separates most solids and impurities from the finished product.

Think of boiling as a disinfection method and distillation as a purification method — both useful, but for different purposes.

Can You Use Filtered Water Instead of Distilled Water?

In most cases, no — filtered water should not be used in place of distilled water for appliances that explicitly require distilled water, such as CPAP machines, humidifiers and steam irons. These devices depend on the absence of minerals, which filtered water may still contain unless it has been treated through reverse osmosis or distillation.

Filtered water is safe and often preferred for drinking, but distilled water is required when mineral buildup could damage sensitive equipment or skew test results.

Is There a Substitute for Distilled Water?

If you don’t have access to distilled water and need a close substitute, reverse osmosis water is the next best option. RO systems filter out most hardness minerals and contaminants, including heavy metals and many chemicals, producing high-quality water that’s often comparable to distilled in purity. Some medical or laboratory applications may still require true distilled water, but RO water is widely used in its place for household needs.

Can I Use Purified Water in My CPAP Machine?

No — most CPAP manufacturers specifically recommend using distilled water. That’s because purified water may still contain small amounts of hardness minerals and other debris, which can accumulate in the humidifier chamber and shorten the life of the device.

If distilled water isn’t available, reverse osmosis water may be an acceptable short-term alternative — but always check with your device’s manufacturer for guidance.

Can I Substitute Distilled Water With Purified Water?

While purified water is suitable for most everyday needs, such as drinking or cooking, it’s not always a good substitute for distilled water. Purification doesn’t have a standard definition, so it’s not always clear what contaminants have been filtered out. If you’re using water for sensitive devices like humidifiers or laboratory equipment, only use distilled water to avoid limescale buildup or performance issues.

Can People Drink Distilled Water?

Yes, distilled water is safe to drink. It’s free from most contaminants, making it a very popular option. That said, it can taste flat or bland due to the lack of minerals.

Some people prefer mineral-rich or filtered water for flavor and electrolyte content, but drinking distilled water won’t harm you.

Is It Better To Drink Distilled or Purified Water?

It depends on your preferences and needs. Both are safe to drink, but there are a few differences:

Distilled water has had nearly all minerals removed, which can give it a flat taste. It’s very high quality, but may not be ideal for long-term hydration unless minerals are added back.

Purified water is a blanket term for filtered water. It retains trace levels of minerals, which may improve the taste while remaining clean and safe to drink.