What Is Distilled Water and Is It Safe to Drink?

Distilled water is the choice of laboratories and pharmacies because of its high purity. A water distiller removes 99.9% of dissolved inorganics, bacteria, and chemicals from water. Despite its high quality, whether or not distilled water is safe to drink is not easy to determine. The effects of drinking distilled water remain an under-researched and frequently debated topic. Essential minerals like calcium, magnesium, and sodium are removed from distilled water along with the harmful contaminants, leading some to worry about whether it's dangerous. 

To understand the advantages and disadvantages of distilled water, it's necessary to consider water's role in the body, the sources of essential minerals, and how the body uses minerals. We are water filtration experts, not scientists or medical professionals, so we've researched common arguments and scientific facts to help you decide if distilled water is the best choice for your health.

Is drinking distilled water safe?

Yes, distilled water is safe to drink. However, you may find it tastes a little flat. Distillation purifies water in a natural process, similar to the earth's hydrologic cycle. There are no added chemicals or disinfectants in the water that can harm you. What's left out of the water is what causes worry.

A water distiller is so good at removing substances from water that nearly everything, including dissolved minerals, is removed. Some of these essential minerals, or electrolytes, are used by the body to carry signals between cells. Our bodies obtain electrolytes primarily through food. Water contains only trace amounts of minerals, but is it enough to make a significant impact? That depends on your health, nourishment, and level of physical activity. 

Common arguments on drinking distilled water:

1. Drinking distilled water creates health problems from the lack of essential nutrients and causes dehydration.
2. Drinking distilled water is never a bad idea because the body cannot absorb dissolved minerals from water into the tissue.
3. Drinking distilled water can be beneficial, but may not be the best choice for everyone, especially if the minerals are not supplemented by another source.

Water makes up 60% of the human body, so it's important to make sure that water is safe and beneficial. We want to provide you with the information needed to determine whether you should choose distilled water or an alternative.

What is distilled water?

Distilled water is water that has been purified by a water distiller by converting water into steam, leaving contaminants, bacteria, and minerals behind. As the steam cools, it condenses back into a liquid and drops into a collection container. Distillation mimics nature's process of recycling water, known as the hydrologic cycle. Home water distillers have one chamber where water evaporates and another where the steam is collected.

Learn more about how a water distiller works.

What does a water distiller remove

A water distiller removes total dissolved solids (TDS) from water, as does reverse osmosis (RO) and deionization (DI). A carbon postfilter is added to a water distiller to remove volatile organic compounds (VOCs) as well. Dissolved inorganic minerals and other contaminants make their way into the water supply as it flows through rich soil, receives chemical disinfection, or travels through pipes. Some dissolved substances like calcium or potassium are harmless, but many like arsenic or lead are dangerous. In excess, even minerals are detrimental to your appliances and health. Water distillers remove dissolved substances from tap water before you're exposed to them, and they're used to convert seawater into drinkable water. 

The Environmental Protection Agency (EPA) sets regulations for the maximum level of contaminants in drinking water for it to be considered safe. Water that contains contaminants above the recommended levels needs some method of treatment, or it could make you sick. A water distiller provides clean drinking water without changing the chemical composition of water. Water without minerals may be more soluble and can absorb metals and other substances from old pipes, which is one reason why distillation is not used for city water treatment. Distillers for drinking water, however, purify water after it flows through pipes, so you're in no danger from chemical leaching.

The level of mineral content in water varies by region. Minerals are harmless, but sometimes even beneficial ones need filtering. Too much calcium creates hard water, which is costly to your appliances. Too much sodium or chloride gives water a bad taste, harms plants, and corrodes plumbing pipes. If you have excessive mineral content in addition to contaminants, a water distiller is one of the best treatment options. 

Here's how contaminants affect drinking water.

What is distilled water used for?

Distilled water is used in applications where water needs to be free from microbes, minerals, toxins, and taste-altering contaminants. The following includes some examples of applications that use distilled water:

• Laboratory experiments
• Medical uses
• Automobile cooling systems
• Cosmetic products
• Canned foods
• Vehicle batteries

Laboratories and hospitals must use distilled water to guarantee that water is sterile, while food processing plants use distilled water to ensure the consistency of products’ tastes. The automobile world uses distilled water in cooling systems and batteries to prevent mineral deposits in the radiator and contaminants in water from corroding the battery.

Learn more: Using distilled water for a PC water cooler

Is distilled water good for you?

Water contains trace amounts of dissolved minerals that may be absorbed in the body. If the body could not absorb inorganic minerals at all, then we would not bother filtering them out of drinking water. However, dissolved minerals are not as easily absorbed as organic compounds, and we receive most of our essential minerals through food. Distilled water may not be a good choice during intense exercise or when you're sick or malnourished. But for most of the people in the U.S., distilled water is not unhealthy. 

Why do you need water?

Drinking water benefits us in several ways:

• Lubricates joints
• Protects cells and vital organs
• Keeps the body from overheating
• Helps remove waste
• Dissolves nutrients 

Supplying you with essential minerals is not one of water's primary responsibilities. If your body is deficient in minerals or other nutrients, drinking water is not the first solution. The body can get trace amounts of minerals from water and some water from food. However, we don't drink water for more nourishment, just like we don't eat food to recover from dehydration. Water's job is to dissolve the minerals you eat so they can easily flow to other parts of the body. 

Water moves through cells and tissues to balance the concentration of solutes and maintain homeostasis, or equilibrium. Water is contained either inside of cells (intracellular fluid) or outside of cells (extracellular fluid).

• Intracellular fluid (ICF): 2/3 of water in the body
• Extracellular fluid (ECF): 1/3 of water in the body

Plasma contains 20% of the ECF and transports minerals including electrolytes.

Here's how: Hydrostatic pressure pushes plasma along with nutrients into cell membranes and tissues. Water flows unrestricted through a membrane, but solutes do not. Many ions, including electrolytes, must be forced through cells and tissues via active transport, which requires extra energy. Passive transport does not require extra energy, but the molecules must be able to pass through the membrane on their own, which is more difficult for ions (Rice University, 26.1). 

What does this tell us? Electrolytes, whether from food or water, don't pass through cell membranes and tissues as easily as water. This means that when you drink mineral water, only a portion of that low mineral content actually benefits the body. 

Why do you need minerals?

Electrolytes are essential minerals that carry signals between cells and transport fluids into your muscles and keep them from cramping. Fruits and vegetables are the best supplements for mineral deficiencies. Calcium, for example, is best supplemented with foods rich in vitamin D, like fish and eggs, and sunlight. 

According to the World Health Organization:

"Individuals who would receive the greatest benefit from the presence of minerals in drinking water are those individuals with marginal intakes from food sources. In the United States, the 50th percentile dietary intakes from food appear to be adequate in most cases, with the exception of iron intakes by women" (2005, p. 88).

If you're malnourished, then you may not be able to replace minerals through food and rely on the mineral content in water. But in the U.S., an excess of certain minerals is a greater problem than a lack of nourishment. For example, many people consume 130-160 mmol/day of sodium a day, but our bodies only require 1-2 mmol/day, which is why high blood pressure (hypertension) is a common problem (Rice University, 26.3). 

Recommended nutrient intakes from the National Institutes of Health.

What does the body do with extra minerals?

When the body takes in too many minerals, the kidney gets rid of them. Your kidney functions better with the more water you drink. Hydration is important because water protects the kidney from exhaustion. Whenever our bodies have more minerals than we need, our brain signals us to drink more water. If you've spent the afternoon at the movie theater eating a large bucket of salty popcorn and feel parched, here's what's happens: 

1. Sodium collects in the ECF.
2. The ECF takes water from the ICF.
3. The brain receives signals from the cells that there's an over-concentration of sodium. 
4. You feel thirsty and realize you need to drink more water. If you don't, you get dehydrated. 

In this instance, distilled water would be a good option because you don't need extra sodium from water. It's possible that if your water contains contaminants or excess mineral content, filtering it helps reduce the work of your kidney. We believe it's better to filter water than to be the filter. 

Should you drink distilled water? 

Distilled water is one of the purest forms of water you can drink. Bacteria and dissolved substances like lead or arsenic endanger your health if not removed. In such cases, the pros of distilled water far outweigh the cons. People trying to limit their sodium intake could also benefit from distilled water.

On the other hand, mineral content in water can make a difference for athletes, the malnourished, or those who are sick and suffer from mineral deficiencies. As intense athletes sweat, they lose electrolytes rapidly. To stay hydrated, drinking water with minerals or a sports drink with added electrolytes may aid performance. If you're sick and vomiting frequently, then your body also needs help replacing electrolytes. If you're malnourished, then you need all the minerals you can get, and water may be your most available option. 

Benefits of distilled water

• 99.99% of harmful dissolved solids and bacteria removed
• No chemicals added
• No extra sodium
• Prevents scale on appliances

Disadvantages of distilled water

• Not energy efficient (takes 3 hours to produce a gallon)
• Tastes flat (low oxygen)
• No mineral content

What pH is distilled water?

Pure distilled water always has a pH of 7, but distilled water that comes into contact with air has a pH of slightly less than 7. Because water distillation purifies water so well, distilled water is pH neutral directly after purification. However, the water absorbs carbon dioxide from the air and reacts with it to form carbonic acid. The pH of water can drop to as low as 5.8 in about two hours of exposure to carbon dioxide.

Is bottled water distilled?

Bottled water is not distilled. Rather, it undergoes some form of filtration process, typically reverse osmosis. The differing tastes of bottled water brands stem from the minerals added to the water after filtration and can also be affected by where the brand sources its water from. The cost and time of water distillation at that scale renders water filtration far more favorable than distillation.

Does distilled water go bad?

When stored properly, unopened store-bought distilled water can last for at least five years. If the water does not come into contact with any contaminants, it can last indefinitely. An opened container of distilled water, on the other hand, is safe to drink for a few weeks and can be used for appliances for about a year. The biggest threats to contaminate distilled water are bacteria and chemicals absorbed through plastic packaging. To extend the water’s shelf life, ensure a proper seal, store it in the refrigerator, and store it in a glass bottle once opened.

How to store distilled water

The way distilled water is stored will greatly affect its shelf life. If your water is unopened, ensure that the seal remains firmly fastened and undisturbed. Whether opened or unopened, storing distilled water in the refrigerator can greatly extend its shelf life, especially when already opened. If you plan to store opened distilled water for an extended period of time, storing it in a glass bottle in the refrigerator will minimize the risk of chemical contamination via plastic packaging. If you are using distilled water for applications other than drinking, contamination may not be as important. However, if distilled water is affected by certain contaminants, it can defeat the purpose of using distilled water for that application in the first place.

Signs of bad distilled water

Distilled water can show multiple symptoms that are clearly noticeable when the water has been contaminated. These include:

• Cloudiness
• Algae growth
• Chemical taste

If your distilled water exhibits any of these symptoms, your distilled water is not safe to drink or to use in other applications.

Alternatives to distilled water

If you don't think distilled water is the best choice for you, then a carbon filter, reverse osmosis system, or an ultrafiltration system may be a more suitable option.

Carbon filter

If TDS in your water is not a concern, then a water distiller may do more than you need. An activated carbon filtration system removes chlorine and other chemicals, as well as contaminants that cause bad tastes and odors. Some carbon filters are also rated to remove lead or cysts. Refrigerator filters utilize activated carbon cores, so they are also an effective solution if chlorine is your main concern.

Learn more about activated carbon filters and refrigerator filters.

Reverse osmosis system with a remineralizing filter 

Reverse osmosis doesn't remove as many minerals as a water distiller, but it doesn't require extra energy. A reverse osmosis system removes VOCs in addition to dissolved solids. You can purchase a system with a remineralizing filter that replaces some of the essential minerals lost. If you're worried about using an RO system due to the amount of wastewater produced, then find one with a permeate pump. A permeate pump increases efficiency by 85%. 

Learn how reverse osmosis works or how to select the best reverse osmosis system.

Ultrafiltration system

If you need to remove microscopic contaminants while retaining dissolved minerals, then an ultrafiltration system is the best option. The ultrafiltration membrane blocks particles 5,000 times smaller than a human hair, but the pores are not large enough to remove dissolved solids. An ultrafiltration system operates on low pressure and does not produce wastewater. 

Learn how ultrafiltration works.

Water distillers for your home

If you think a water distiller is right for you, browse our water distillers or find one below. To maintain your water distiller, change the carbon postfilter regularly to reduce VOCs and clean the jug to prevent contamination.