Distilled water stirs up a lot of controversy.
You may have read that drinking it is beneficial, or that it might cause health problems.
This article takes a look at distilled water and its potential effects on health.
Distilled water is water that has been purified through distillation.
Distillation is when you boil water and then condense the clean steam into a new container.
This gets rid of all impurities, minerals and other substances, producing relatively pure water.
The practice of distilling water has been around for thousands of years. It was originally used to remove salt from sea water for drinking purposes.
Today, it's used in applications that require mineral-free, pure water, such as in chemistry labs, hospitals, automotive care and aquariums.
In addition, distilled water is sometimes used for brewing certain types of beer, such as Pilsner. However, its flavor may not be suitable for all types of home brews.
Finally, distilled water is also consumed as a beverage or used in cooking the same way tap water or bottled water is.
Bottom Line: Distilled water has had its impurities and minerals removed. It's typically used in laboratories, hospitals, cars, aquariums and brewing beer, as well as for drinking like regular water.
Distilled water is made by boiling water to produce steam, which is then cooled and condensed into water.
Since contaminants and most minerals have a higher boiling point than water, they are left behind.
The most common home distiller, which is known as a single-unit distiller, heats water in a chamber until steam develops.
The steam is drawn away from the chamber, cooled and condensed into water, leaving contaminants in the chamber.
Vapor-compression distillers can produce up to 5,000 gallons of water per day. They use a single chamber to convert water to steam. The steam then passes through a compressor and condenses into water in a final chamber.
Finally, multiple-effect distillers contain boiling chambers that are connected by tubes and can provide millions of gallons of distilled water per day for commercial use.
Bottom Line: Distilled water is produced by heating water to produce steam, which is then condensed into water that is free of impurities and minerals.
Distilled water may have some benefits over other types of water.
Distilled Water Is Free of Chemicals and Toxins
Because all of its impurities are left behind during the distillation process, distilled water is essentially free of chemicals.
Most countries monitor tap water to ensure that it meets standards for chemicals and other contaminants.
However, safety levels haven't been established for all chemicals in water, including certain pesticides and herbicides. One study found up to 13 herbicides in drinking water from a rural US area, only 7 of which had established safety levels (1).
In addition, some researchers believe that current screening methods may not accurately detect levels of potentially toxic compounds known as disinfection by-products (DBPs), which are produced during the process of killing bacteria (2, 3, 4).
Levels of pesticides and other chemicals in tap water will also depend on your geographic location and the regulatory agencies in your country.
In contrast, properly distilled water contains no pesticides, herbicides or chemicals. It's simply 100% pure water.
Bottom Line: Distilled water is free of chemicals and toxins that can be found in drinking water.
Distilled Water Is Free of Bacteria and Other Germs
Tap water in Western countries is generally within accepted safety limits for bacteria, viruses and other germs. However, these microbes are present in small amounts in virtually all public drinking water supplies around the world (5, 6).
Occasionally, they may temporarily reach unsafe levels when water is accidentally contaminated (7).
However, even small amounts of bacteria in tap water may pose health risks in people with weakened immune systems, such as those with certain types of cancer or HIV/AIDS.
Distilling water removes all bacteria and other organisms that are sometimes found in drinking water.
Bottom Line: Distilled water contains no bacteria or other germs typically present in small amounts in tap water. This may make it more suitable for those with certain diseases.
Distilled Water Is Free of Chlorine
For more than 100 years, chlorine has been used as a disinfectant in drinking water. It's generally considered safe and effective for killing germs and preventing diseases that spread via the water supply.
The EPA sets a safety level of 4 mg per liter or 4 parts per million, which is strictly monitored.
Furthermore, some people find the smell or taste of chlorinated water unpleasant.
Distilled water contains no chlorine or DBPs, although the chlorine-removal process differs from the process of removing other impurities.
Unlike most minerals, chlorine has a lower boiling point than water and so do DBPs. Because of this, they are boiled off separately in the preheating phase of distillation or removed via carbon filters.
Bottom Line: Chlorine and potentially harmful DBPs are present in drinking water in small amounts. Distilled water contains no chlorine or DBPs.
There are several myths about drinking distilled water.
Distilled Water Leads to Health Problems by Removing Minerals
In addition to removing chemicals and bacteria from water, the distillation process also removes the minerals.
However, only very small amounts of minerals are found in water.
For instance, average water in the US water supply provides 60 mg of calcium in 2 liters of water, which is only 6% of the RDI.
By contrast, a single cup (244 grams) of milk contains 276 mg of calcium, which is 28% of the RDI.
Cooking Foods in Distilled Water Causes Mineral Loss
Mineral losses during cooking are related to the cooking method, rather than the type of water used (9).
Cooking with distilled water doesn't cause food to lose more minerals than cooking in tap water.
Distilled Water Causes Dental Decay and Discolored Teeth
Although distilled water lacks fluoride, brushing your teeth with toothpaste will provide adequate amounts of fluoride. There is no evidence that drinking distilled water causes tooth decay or discoloration.
Distilled Water Is Too Acidic
Removing minerals from water will lower its pH, making it slightly more acidic than tap water.
However, there is no evidence that this causes harm. Healthy people's bodies are very efficient at maintaining their pH levels.
Bottom Line: Some say distilled water has had too many minerals removed, leads to mineral losses during cooking, causes dental problems and is too acidic. However, none of these are supported by science.
Drinking distilled water doesn't appear to have any negative health effects.
Some people may not like its taste for drinking or cooking purposes. However, it isn't harmful and may even be beneficial for people with weakened immune systems.
Whether to drink distilled water is a personal choice. At this point, there isn't any compelling evidence showing that it's any better or worse than other types of water.
More about water: