Distilled vs. Purified Water: What's the Difference?

So you want the cleanest water. Makes sense, as contaminants have been shown to cause stomach illness, reproductive problems, and neurological disorders. Clean water is especially important for infants, pregnant women, elderly people, and those with compromised immune systems as they are at higher risk of illness.

But should you be choosing a distilled water or a purified water? And how are the two different anyway?

What's the Difference Between Distilled Water and Purified Water?

Both distilled water and purified water undergo a distinct vetting process that makes them safe to drink. Here's a closer look at those approaches, along with details on some common uses for each type of water.

Distilled Water

Distilled water is made by collecting the steam from boiling water, then recondensing and bottling it. That process essentially gets rid of contaminants, including salts, metals, minerals, asbestos, particles, and some organic materials.

"The distillation process extracts the basic molecules of water (H2O) and isolates them from most minerals and electrolytes that are dissolved within water," says David Kahana, MD , a board-certified doctor in medical nutrition and formulator for 1MD Nutrition in Los Angeles.

Stripping the water of those minerals results in a flat taste - but on the other hand, the water is rid of up to 99.5 percent of water impurities.

Drinking distilled water could be helpful for people with weakened immune systems, who might react to traces of bacteria in water.

It's also recommended to be used in medical devices, such as CPAP machines, to prevent mineral buildup, Dr. Kahana says. There are a few potential downsides. Distilling water doesn't remove volatile organic chemicals because they have a boiling point of less than or near that of water, so they may end up in the distilled version. And some of the minerals removed are healthy ones - such as electrolytes, including calcium and magnesium - Kahana says. Another negative is the cost. You can purchase bottles of distilled water or install a distillation unit at home, which is expensive to set up and maintain.

Purified Water

Purified water starts out as regular water that is treated to remove all chemicals and pathogens per the U.S. Pharmacopeia's guidelines.

That process removes microbes and heavy metals such as lead, but retains some minerals and electrolytes, Kahana says.

Purified water is used in many countries where water is not safe for human consumption. Like distilled water, it can be expensive to purchase an in-home filter or bottles of purified water, which can also be wasteful. Another downside is purified water usually lacks fluoride , which is important for dental health.

"However, [fluoride] can also be obtained from other sources such as toothpaste, mouthwash, and dental treatments," says Michelle Routhenstein, RD , a preventive cardiology dietitian at EntirelyNourished.com based in New York City.

While both types of water are healthy and strip water of bacteria, chemicals, and other contaminants, purified water may have a slight advantage because it maintains more of water's healthy minerals (other than fluoride), Kahana says.

Take that with a grain of salt, though, because most people source the minerals, vitamins, and electrolytes they need from their diet rather than their water intake, Routhenstein says.

Tips on Adding Purified Water to Your Healthy Diet

Ultimately, the most important thing is that you're drinking water . Even tap may be okay for you, depending on where you live. In sum, whichever version helps you consume more is the right one for you. "Water is the universal solvent and the basic building block of life, so drinking water is essential on every level," Kahana says.

Not sure if you're getting enough? Try the following tips from the Centers for Disease Control and Prevention to increase water intake:

• Carry a water bottle with you. This way, you will always have it on hand.
• Try infusing new flavors into your H2O. Consider adding lemon or lime to your water if that improves the taste for you and makes you more likely to sip it throughout the day.
• Limit or avoid sugar-laden beverages. Choose water versus sugary soft drinks when eating out and at meal times at home.

The Takeaway

Distilled water removes metals, minerals, and other impurities, but it also removes some important minerals. Purified water removes chemicals, metals, and fluoride while retaining some minerals and electrolytes. Ultimately, the best water is the water that you drink. Sometimes even tap is best, so long as it's safe.

Editorial Sources and Fact-Checking

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