Distilled Water: Uses, Safety and Side Effects

Distilled water is water purified by boiling it into steam such that contaminants and minerals are left behind, and then cooling and condensing it back into a liquid. It is suitable for drinking, medical sterilization, and manufacturing processes where the buildup of minerals needs to be avoided. Because it lacks minerals or dissolved gases, distilled water has a very flat, laboratory-like taste that many people do not enjoy.

Because distilled water does not have any beneficial minerals such as calcium, magnesium, or potassium, distilled water does not provide the body with those benefits. People obtain most of their minerals from food, so drinking distilled water is not a problem in and of itself, though it lacks the benefits that most tap, purified, and mineral water provides.

There are concerns that drinking distilled water on a regular basis increases urine output to unhealthy levels, or that it dilutes electrolytes in the body. While there is no scientific consensus around these points, it does make sense for daily drinking purposes to choose water with some mineral content to avoid the possibility of any such issues.

What Is Distilled Water?

Distilled water is water purified by boiling it and recondensing the steam into liquid. Boiling the water means that impurities, minerals (harmful and beneficial), biological contaminants, and dissolved gas are left behind and removed from the finished water. Some impurities with a boiling point at or above the boiling point of water may not be removed by the process.

Distilled water is made by raising the temperature of the water to the boiling point, allowing the steam to rise and then recondense into liquid in a cool-down chamber.

Distillation is one of the most effective forms of water purification, creating a liquid excellent for industrial, medical, and other uses that require extremely pure, non-mineralized water.

Distillation is one of the oldest forms of water purification. It was used to desalinate seawater as long ago as the third century AD by Alexander of Aphrodisias, according to a report by science historian F. Sherwood Taylor in the Annals of Science.

This image from a 15th-century Byzantine Greek manuscript shows the distillation equipment that the 3rd-century alchemist Zosimus of Panopolis used.

How Is Distilled Water Made?

Distilled water is made by boiling the source water, cooling it, and collecting the steam. There are three main methods of water distillation.

• Simple distillation. The most basic form of distillation is to boil the source water at 100 °C, let the steam rise into a separate chamber, tube, or condensing coils where it cools, and then collect the pure water as it condenses.
• Multi-stage flash distillation (MSF). In this process, the liquid is placed under high pressure. This lowers the boiling point down to the ambient temperature, turning it into steam without heating it. The steam is then passed to a lower pressure chamber where it recondenses.
• Fractional distillation. The heating, evaporation, and condensation steps are repeated at different temperatures. There is rarely a need to do this with water since it has a single boiling temperature, but the process is used for petroleum refining as different products boil at different temperatures.

These diagrams show the three main types of how to distill water.

What Is Distilled Water Used For?

Distilled water is used for sterilizing medical equipment, lead-acid batteries, automotive cooling systems, and other devices where mineral buildup would cause damage. The absence of other minerals and contaminants makes it ideal for use in skin products, canning products, and cleaning laboratory equipment.

• For cosmetic use: Most cosmetic products contain water that needs to be microbe, toxin, and pollutant-free, making distilled water the best choice.
• In lead-acid batteries and automotive cooling systems: Distilled water is suitable for use in devices where mineral deposits could cause corrosion and build-up that interferes with operations. This includes lead-acid batteries and automotive cooling systems, as well as many types of industrial equipment.
• Medical Uses: The high purity level of distilled water makes it ideal for sterilizing medical instruments, as it does not leave residue or deposits. It is used by surgeons to sterilize and prevent infections and cross-contamination, and by emergency personnel to clean wounds. Dentists use distilled water to rinse the mouth and wash away bacteria. Distilled water is also preferred in Continuous Positive Airway Pressure (CPAP) machines, as it prevents bacteria from breeding.
• In the food industry: Distilled water is used in the canning process to ensure the food’s flavor remains the same. Salts and minerals in non-distilled water types could alter flavors.
• In Fish Tanks and Aquariums: Tap water contains minerals and chemicals that might be harmful to fish in an aquarium. Distilled water serves as a neutral form of water whose qualities such as pH or salinity can be adjusted to the needs of whatever aquatic life is being maintained.

This infographic shows some of the most common uses for distilled water.

Is It Safe to Drink Distilled Water?

It is safe to drink distilled water according to the 1980 guidelines by WHO. Distilled water is safe for drinking, but it can have negative taste characteristics and does not contain healthy minerals. The same report goes on to mention that distilled water is reported to be less thirst-quenching and that although this is not considered to be unhealthy, poor organoleptic and thirst-quenching characteristics may affect the amount of water consumed.

According to the Centers for Disease Control and Prevention (CDC), the distillation process is very effective at removing protozoa (such as cryptosporidium or giardia), bacteria (such as campylobacter, salmonella, shigella, E. coli), and viruses (including enteric, hepatitis A, norovirus, and rotavirus). Distillation also removes chemical contaminants, including arsenic, barium, cadmium, chromium, lead, nitrate, sodium, sulfate, and many organic chemicals, according to the CDC.

Along with contaminants and bacteria, distillation also removes minerals that are beneficial for the body. Based on this, it can be deduced that drinking distilled water is safe, but not necessarily healthier than most other types of clean drinking water.

For those wondering "can you drink distilled water?", a good answer comes from Frank N. Hepburn, Chief, Nutrient Data Research Branch at the US Department of Agriculture. "There is nothing about distilled water that would make it harmful for the body. It may be helpful to remember that distilled water is the only water available for crews of Naval vessels at sea."

This graphic shows the four main types of compounds that are removed from distilled water.

What Are the Benefits of Distilled Water?

The benefits of distilled water include providing extra purity for those with compromised immune systems, and possible assistance in successful surgeries for some cancers.

Immunocompromised people are more susceptible to health problems from chemical contaminants. People with cancer undergoing chemotherapy, organ transplant patients, people with HIV/AIDS or other immune system disorders, and some elderly and infants can be particularly at risk from infections. Compared to municipal water sources, distilled water is less likely to contain the sorts of contaminants that could put immunocompromised people with cancer at risk.

Properly handled distilled water does not contain biological contaminants such as the parasite cryptosporidium which are more dangerous for the immunocompromised. According to a 2013 report by Kerri A. Thom at the University of Maryland Department of Epidemiology and Public Health, drinking sterile water (including distilled water) is beneficial for the health of high-risk patients as it protects against water-borne infections.

Drinking distilled water may help with certain cancer surgeries. A 2004 study by the Department of Colorectal Surgery at West Suffolk Hospital in the UK examined whether utilizing distilled water instead of sanitizers during colorectal cancer surgery could assist in destroying cancer cells. They found distilled water in laboratory cultures has effective tumoricidal properties, though current surgical methodologies are inadequate and would need to be changed to provide longer exposure of cells to the distilled water.

What Are the Risks of Using Distilled Water?

The risks of using distilled water are getting fewer healthy minerals in your diet, dilution of electrolytes in the body, and increased urine output, which could cause dehydration problems. The main risks from drinking distilled water are not problems caused by distilled water as a substance, but simply the absence of positive minerals.

The WHO Guidelines for Drinking Water Quality take no position on risks from drinking distilled water. However, 2004 research for the guidelines by Frantisek Kozisek identified some potential risks.

• Experiments reviewed in the WHO study indicated consumption of pure distilled water led to increased urine output or diuresis of around 20% on average. This could lead to dehydration problems.
• The absence of important minerals in distilled water (sodium, potassium, chloride, calcium, and magnesium ions) led to the dilution of electrolytes dissolved in the body’s water. The intestine requires these minerals and takes them from the body’s reserves. This causes inadequate body water redistribution between compartments, which may compromise the function of vital organs. Symptoms at the very beginning of this condition could include exhaustion, weakness, and headache and can escalate to muscular cramps and impaired heart rate.

This graphic shows some of the important electrolytes and minerals missing from distilled water and what they do for the body.

Distilled water research in the 1970s in the Soviet Union did suggest possible more serious risks from distilled water such as heart disease and diabetes, but the results have not been confirmed elsewhere and were not considered solid enough to drive recommended actions.

The lack of minerals in distilled water is the main cause of its health risks. However, water is not the body’s primary source of minerals such as iron, magnesium, and potassium. The Water Quality Association states that "The amounts of minerals found in water are insignificant when compared to those found in the foods we eat. Because tap water varies substantially in the amount and proportion of mineral content, the most reliable source of those essential mineral nutrients come from a normal daily diet consisting of fish, meat, and vegetables."

What Are the Things to Consider before Drinking Distilled Water?

The main things to consider before drinking distilled water are your taste preferences and whether you have enough healthy minerals in your diet.

TDS (total dissolved solids) is the amount of minerals dissolved in water and is one of the most significant factors in giving the water its taste. The TDS of distilled water can be as low as 1-2 ppm (parts per million). This and the fact that distillation removes dissolved gasses such as oxygen gives distilled water a flat “laboratory” taste. Many people find this taste undesirable, but it is a matter of personal preference.

It is worth noting that because other super-low TDS waters such iceberg water and rainwater retain atmospheric gasses, they have a light and fresh taste very different from distilled water.

If your regular food intake is lacking in sufficient healthy minerals like calcium, magnesium, and potassium, water that is not distilled can be a useful supplement. However, the amount of these minerals and electrolytes in most tap and bottled water is minimal, so drinking distilled water will usually not have a meaningful impact on one’s total mineral intake.

Lisa Richards, nutritionist and author of ​the Candida Diet, recommends including adequate nutrients in the diet to balance any health impacts of drinking distilled water which is devoid of calcium, magnesium, and other beneficial elements. "When they (electrolytes) are missing in our primary hydration source, as well as our diet, we risk severe dehydration and chemical imbalances leading to serious health concerns," she noted. If you’re going to drink distilled water, get your recommended daily servings of nutrition through fruits and vegetables.

What Is the pH of Distilled Water?

The pH of distilled water ranges from 5.8 to 7. Pure distilled water in a sealed system has a pH of 7, but as soon as it is exposed to the air it begins to absorb atmospheric gasses including CO2 and starts to become acidic. If any trace elements are left in the water after distillation, this can also alter the pH.

For a pH definition, the simplest explanation is that the pH of water measures the degree of its acidity or basicity (alkalinity), and is expressed on a scale of 0 to 14. Water with a pH of 7 is neutral. “pH” less than 7 is acidic, with 0 the most acidic. More than 7 is basic or alkaline, with 14 the most basic. This graphic shows the pH levels of different types of drinking water.

The pH of water usually has no direct impact on health or safety, but is an important parameter that has to be monitored because pH affects the way water interacts with its environment and can thus impact the susceptibility of water to other impurities.

Except at extreme levels far beyond any potable water, the pH of water has no harms or benefits to human health. According to The Merck Manual of Diagnosis and Therapy, the human body uses buffers to balance the pH. If a person consumes something acidic, the blood will produce more bicarbonate and less carbon dioxide to neutralize the acidity. Likewise, the blood will produce more carbon dioxide and less bicarbonate if an alkaline substance is consumed. Meaning that alkaline water will not raise the body’s pH level, acidic water will not lower it, and distilled water will not balance it.

What Other Water Types Are Similar to Distilled Water?

Other water types similar to distilled water are deionized water, reverse osmosis water, and arctic water from icebergs. The following are the definitions of these types of water.

• Deionized Water: Feed water is processed in ion exchange resins which remove ionized salts. Deionization can remove 100% of salts when performing at optimum levels, but typically does not remove organics, viruses, or bacteria except through “accidental” trapping in the resin.
• Reverse Osmosis (RO) Water: Reverse osmosis is a process that uses a very fine membrane under pressure to separate impurities from the feed water. As with distillation, it also removes most minerals, both beneficial and harmful. The process is energy-efficient and operates at low temperatures, making it one of the most common ways to treat water. Because the water is very pure, it is used for dialysis in hospitals, cosmetics, and manufacturing of some drugs by pharmaceutical manufacturers.
• Arctic Water from Icebergs: There are few natural waters with similar high degrees of purity and low mineral levels as distilled water, but arctic water from icebergs is one of the closest. Because it is snow that was preserved as ice almost immediately after falling from the sky thousands of years ago, it is devoid of modern pollutants. Because it never made contact with any ground geology, it has an extremely low TDS level. The pH tends towards the low end of distilled water’s range because iceberg water has absorbed atmospheric gasses.

This image shows a simplified diagram of the Reverse Osmosis water purification process from the University of Aachen’s contribution to the iGEM project.

What Is the Difference Between Distilled Water and Purified Water?

The main difference between distilled water and other types of purified water is that while both have no chemicals or contaminants, purified water still contains minerals while distilled water has almost all of them removed. Distilled water technically is a form of ultra-purified water.

The EPA describes purified water as water that has been mechanically filtered or processed to remove impurities like bacteria, viruses, chemical pollutants, and harmful minerals like lead and copper. In most developed countries, including the United States and Canada, tap water is purified to ensure it is safe for consumption.

If you wonder whether distilled water is the same as purified water, you are not alone. Lisa Richards, nutritionist and author of ​the Candida Diet​ explains, "Distilled water is purified water that has had both contaminants and minerals removed, while purified water has had only contaminants removed". The absence of minerals and dissolved gases give distilled water a flat taste. Most purified water still has minerals in it, which gives it a taste that is easily perceptible when compared to distilled water.

This video shows how tap water purification works, removing impurities but not minerals the way distillation does. Purified bottled water and even home water purification systems use similar processes, though usually with fewer steps.

What Is the Difference Between Distilled Water and Arctic Water?

The main difference between distilled water and arctic water is that distilled water has no minerals or dissolved gasses such as oxygen and CO2, while arctic waters do have them in varying degrees.

Arctic water can refer to iceberg water such as Svalbarði or glacial meltwater, which may be found in surface water or springs. Iceberg water has very low mineral content because it is preserved ancient snow that never touched the ground, but it does have dissolved gasses from when it fell from the sky. This means it has an airy, fresh taste compared to the flat, laboratory taste of distilled water.

Glacial meltwater in streams or other surface water picks up minerals from the ground and gasses from the atmosphere. It is also exposed to potential contaminants, chemical and biological, and so must be at least minimally purified to ensure it is safe to drink.

Glacial meltwater that has seeped into the water table and emerges from a spring will have picked up the minerals from the geologic strata it passes through, meaning it can have a low, medium, or high TDS depending on the local geology. Presuming the region is not polluted, the geological strata also naturally filter the water so that it usually emerges pure from the ground.