Distilled Water

You’ve probably faced this choice while dining out: Tap, bottled, or sparkling water?

But what about distilled water?

It’s not that different from what flows out of your kitchen faucet. But distilled water goes through a process that sets it apart from other types of H2O.

What Is Distilled Water?

Distilled water is steam from boiling water that’s been cooled and returned to its liquid state. Some people claim distilled water is the purest water you can drink.

All water -- no matter if it comes from a natural spring, artesian well, or regular tap -- may have trace but safe amounts of minerals, bacteria, pesticides, and other contaminants.

Distilling rids water of all those impurities. It also removes more than 99.9% of the minerals dissolved in water.

Tap Water vs. Distilled Water vs. Filtered Water vs. Purified Water

As the name says, tap water is the one that comes out a faucet. It has likely been disinfected with chlorine, plus filtered to remove sediments and treated with chemicals to neutralize dirt. Fluoride has also been added to prevent tooth decay. 

Filtered water is tap water that has been run through filters to remove chlorine (this improves the taste) and other things such as bacteria and some chemicals. Different types of filters remove different things. Most bottled water is filtered in some way.

Purified water is water that is essentially free of microbes and chemicals.  This is achieved by reverse osmosis (forcing the water through a membrane to get rid of chemicals, minerals and microbes), ozonization (disinfecting water using ozone rather than a chemical), or distillation. The EPA requires purified water to not contain more than 10 parts per million of total dissolved solids in order to be labeled purified water.

Distilled water is a type of purified water. Salts, minerals, and other organic materials are removed by collecting the steam from boiling water.

Is Distilled Water Safe to Drink?

Distilled water is safe to drink. But you’ll probably find it flat or bland. That’s because it’s stripped of important minerals like calcium, sodium, and magnesium that give tap water its familiar flavor. What’s left is just hydrogen and oxygen and nothing else.

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Uses of Distilled Water

Distilled water is ideal for when purity is important. Common uses include:

  • Medical tools and procedures. Hospitals clean equipment with it to help avoid contamination and infections. Kidney dialysis machines use ultra-pure water to filter waste from blood.
  • Lab tests. Nothing in distilled water reacts with or affects the accuracy of lab experiments.
  • Cosmetics . If water is an ingredient in your moisturizer, deodorant, or shampoo, it’s almost always distilled.
  • Automobiles. Since it lacks minerals, distilled water won’t corrode metal engine parts or interfere with batteries.

At home, you may want to reach for distilled water for cooking and several other reasons, including:

  • Infant formula. Mix it with infant formula if your baby has weak immunity. Otherwise, tap water is fine.
  • CPAP machine. Fill the water chamber for a CPAP humidifier if you use it for sleep apnea. Many manufacturers recommend distilled water to make the humidifier last longer.
  • Neti pot. Use it with a neti pot to clear your sinuses.
  • Iron. Use it in your clothes iron to prevent scale buildup.
  • Shampoo your  hair Fluoride, chlorine, and other additives in the water from your shower may dull your hair.

Risks of Using Distilled Water

Distilled water lacks even electrolytes like potassium and other minerals your body needs. So you may miss out on a bit of these micronutrients if you drink only the distilled stuff.

Some studies have found a link between drinking water low in calcium and magnesium and tiredness, muscle cramps, weakness, and heart disease. Also, distilled water may not help you stay hydrated as well as other kinds of water.

If you use distilled water for your fish tank, be sure to add a sea minerals supplement to the aquarium. Some coffee fans think that distilled water makes for a purer-tasting cup. But the Specialty Coffee Association of America says that a certain level of minerals is ideal in order to extract the best brew.

Storage

Unopened bottled distilled water from a store lasts basically forever. But stash it away from direct sunlight. And once it’s opened, be sure to close it up well after use. Certain germs can grow even in nutrient-poor distilled water.

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How to Make Your Own Distilled Water

  • Fill a large pot of water halfway.
  • Tie a cup to the pot’s lid so the cup will hang rightside up inside the pot when the lid is shut. The cup should be high enough inside the pot that it does not touch the water. 
  • Boil the water for 20 minutes. Boiling creates vapor that rises and then condenses back into water. 
  • The water that drops from the lid into the cup is distilled.
WebMD Medical Reference Reviewed by Arefa Cassoobhoy, MD, MPH on July 01, 2020

Sources

SOURCES:

U.S. Environmental Protection Agency: “Water Health Series.”

University of Georgia Extension: “Water Quality and Common Treatments for Private Drinking Water Systems.”

International Bottled Water Association: “Types of Water -- Bottled.”

Stanford Magazine: “Don't Drink the Water (From Your Dehumidifier): Nitty-Gritty.”

CDC: “Healthy Water: Medical and Dental Equipment,” “Healthy Water: Water Use in Hemodialysis,” “Background D. Water.”

Cosmeticsinfo.org: “Find an Ingredient: Water.”

Distilled Water Association: “Using Distilled Water For Your Fish Tanks: How to Make It Safe.”

The Distilled Water Company (UK): “How Long Does Distilled Water Last? Shelf Life & Storage Uncovered.”

Word Health Organization: “Health Risks from Drinking Demineralized Water.” 

Journal of General Internal Medicine: “Comparison of the Mineral Content of Tap Water and Bottled Waters.”

Seattle Children’s: “Bottle-Feeding (Formula) Questions.”

Nutrients (Switzerland): “Impact of Isotonic Beverage on the Hydration Status of Healthy Chinese Adults in Air-Conditioned Environment.”

Specialty Coffee Association of America: “Water for Brewing Standards.”

CDC: “Community Water Treatment,” “A Guide to Drinking Water Treatment Technologies for Household Use,” “Choosing Home Water Filters & Other Water Treatment Systems.”

EPA: “Water Health Series Bottled Water Basics,” “Red Cross, “Food and Water in an Emergency.”

Science Direct: “Water Filtration.”

© 2020 WebMD, LLC. All rights reserved.

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