Yes, you can drink distilled water safely, though it is best if it is part of a balanced diet. This is because the distillation process which produces it removes healthy trace elements from it such as calcium and magnesium. Other natural and purified waters generally contain at least some of these minerals.
So, can I drink distilled water? Yes, distilled water is harmless if you are getting sufficient electrolytes and minerals from your regular diet of food and beverages. However, the regular consumption of distilled water is not ideal because it may reduce one’s desire to drink sufficient water.
The negative taste and reported poor thirst-quenching aspect of distilled water actively discouraged people from drinking it in a report compiled for the WHO in 2004 titled “Health Risks from Drinking Demineralised Water”. There were also few unsubstantiated instances of adverse effects on the surface of the gastrointestinal (GI) tract.
All the possible adverse health effects point to the absence of electrolytes and minerals that are removed from the water in the demineralization process. Some of the adverse effects could be fatigue, muscle cramps, heart disease, and general weakness. However, a proper food diet offsets any such risks.
Is Distilled Water Safe To Drink?
Distilled water is safe to drink as it has no harmful ingredients, and it is safe to drink in the long term so long as you eat a balanced, healthy diet from which you can obtain healthy nutrients such as calcium and magnesium which distilled water lacks. If you are not obtaining sufficient healthy minerals from your diet, then you should ensure your regular drinking water contains them.
There is some debate amongst scientists and medical personnel over potential negative health effects of distilled water due to its almost total lack of minerals. Some studies conducted in Scandinavia, Canada, the US, and the UK suggest that water stripped of minerals like calcium and magnesium have a direct correlation with an increase in heart disease.
Other researchers believe the correlation is dependent on factors other than the levels of minerals the population is getting from the drinking water. These may include diet and lifestyle factors.
Many people find the taste of distilled water off-putting with a flat “laboratory taste”. This is because it has not just minerals and impurities removed, but also dissolved oxygen and natural gasses that contribute to fresh taste. This could reduce water intake and good hydration if it is the only water available, but in itself it is not a safety problem.
This video explains the factors that impact the taste of water and why distilled water tastes the way it does.
Does The World Health Organization Recommend Distilled Water?
The World Health Organization (WHO) neither recommends nor does not recommend drinking distilled water. The organization’s most recent “Guidelines for drinking-water quality) published in April 2017 states that “There is insufficient scientific information on the benefits or hazards of long-term consumption of very low mineral waters to allow any recommendations to be made”. The WHO also gives no guidelines as to the benefits of drinking distilled water versus water purified in other ways.
The WHO has reviewed data from earlier studies on long-term drinking of public water supplies with varying levels of total dissolved solids (TDS, a measure of the minerals in water measured in milligrams per liter). An early 1980 WHO internal working document pointed to older studies in the Soviet Union that suggested higher TDS municipal water supplies resulted in better health outcomes for the population. However, these studies did not meet current scientific standards and the organization’s Guidelines for drinking-water quality (GDWQ) does not consider them a basis on which to make any recommendations for mineral content in drinking water.
The WHO does state that drinking water can play an important role in a population’s general health by delivering essential trace amounts of micro and macro-nutrients in the diet such as calcium, sodium, magnesium, etc. Distilled water cannot do this.
Health benefits outlined in the report “Diet and Health: Implications for Reducing Chronic Disease Risk” by the National Research Council (US) Committee on Diet and Health are shown below.
What Is Distilled Water?
Distilled water is water purified by evaporating and re-condensing it, leaving behind most pollutants, minerals, dissolved gasses, and bio-contaminants.
To produce distilled water, the source water is heated until it becomes steam. Any compounds or molecules that do not vaporize remain behind while the water molecules transition into a gaseous state. The steam then passes into another chamber where it is cooled down to condense back into a liquid state. This liquid form of water in the final step of distillation produces pure, distilled water free from most contaminants, minerals, or dissolved gasses.
This diagram shows a basic water distillation process, including condensing the vapor back into water by surrounding the pipe the vapor passes through with a jacket of colder water.
This method of water purification is very efficient at eliminating metal molecules such as iron and lead, as well as nitrates. The “hardness” of the water is reduced to virtually zero by removing molecules of calcium and magnesium. Particulate matter is also eliminated. The heat required in a standard distillation process is also adequate to kill off most bacteria or viruses.
The elimination of other chemical contaminants depends largely on their chemical characteristics, like their boiling point and solubility. If the contaminant boils at higher temperatures than water, it will not vaporize and be left behind. But if the boiling point is lower, it will vaporize together with the water molecules and continue to contaminate the distilled water.
There are some pesticides that boil at higher temperatures than water and will effectively be removed by distillation, but organic compounds like benzene and toluene (which are hydrocarbon gasoline components) cannot be removed because they evaporate before the water molecules do and will contaminate the end product.
These are three main types of distillation.
- Simple distillation. This is the basic process of boiling water to vaporize it and leave behind non-H2O components, followed by condensing.
- Multi-stage flash distillation (MSF) is a process where the liquid to be purified is passed from one container under high pressure into a container that is under lower pressure. This causes the liquid to form a gas which is then condensed. Pressure is essentially used instead of heat to cause vaporization and condensation, leaving non-H2O components behind. MSF is commonly used in large seawater desalination plants.
- Fractional/differential distillation can produce distilled water and is also used to process crude oil into petroleum products such as gasoline. In this process, the steps of evaporation and condensation are repeated multiple times at different temperatures to “boil off” different components of the liquid.
Is Drinking Purified Water Better Than Distilled Water?
Yes, most purified water is better than distilled water on a health and taste basis. Distilled water actually is a form of purified water. However, unlike distilled water, most commercially available purified water (tap and bottled) either keeps healthy minerals in it or has them added back in, which also improves taste.
For uses other than drinking, there are industrial and scientific applications where distilled water is needed such as to maintain sanitary conditions or prevent fouling of equipment. This diagram outlines some of the non-drinking applications where distilled water is best.
Purified water is water that has undergone various processes to remove physical, biological, chemical, or radiological contaminants and impurities. These may include bacteria, viruses, pesticides, organic and inorganic compounds, heavy metals, hydrocarbons or any of hundreds of potential contaminants.
Purification ensures water is safe to consume, clean with, or bathe in. In most developed countries the public drinking tap water has been purified and is safe to consume from the tap directly. Most purified water maintains or has added minerals and nutrients for health. Some has disinfectants like chlorine added to ensure it remains safe in transit between the purification plant and the end consumer.
Purification methods include:
- Coagulation and flocculation: Special chemicals with positively charged ions are mixed with water and this binds to all negatively charged particles to form larger molecules called flocs. These are then easier to physically filter out.
- Sedimentation: Water is kept still in a tank, allowing larger impurities to settle via gravity to a sand bed at the bottom where they can gather and be removed.
- Filtration: Water is passed through various filters made of sand, activated carbon, gravel, or microscopically fine mesh. Filtration removes extremely small physical contaminants, bacteria, viruses, dust, or metals depending on the size and characteristics of the filter.
- Reverse osmosis: Passing water through an extremely fine membrane via pressure differentials, removing virtually all contaminants and minerals.
- Distillation. Boiling and recondensing water to leave behind contaminants.
- Deionization: A process of removing ions that are contaminants from water.
- Chemical disinfection: Chemical disinfectants, like chlorine, are added to the filtered water to sanitize the water from any biological contaminants like bacteria or viruses that may have passed through prior few steps.
- UV disinfection: The water is passed through a chamber of ultraviolet light which inactivates or destroys bacteria and viruses.
- Ozonation: Oxygen in the form of ozone (O3) is introduced into the water where it is a powerful disinfectant that destroys viruses, bacteria, and cysts as well as removing some metals. It dissipates quickly and leaves safe, clean water behind.
Every country, state, or city has its own water safety regulations that have to be met before purified water is legally ready for human consumption or other use. Some regulations related to water contamination are far stricter than others, Places such as California, the United Arab Emirates, and Singapore are examples of strict water contamination regulations. All contaminants can never be entirely removed, but acceptable levels are not difficult to reach. Natural waters such as mineral water, spring water, arctic water including iceberg water, and artesian water are naturally extremely pure and some require no further purification processes to be drinkable and healthy.
Municipal water purification systems do require significant capital investment to build and maintain. This video gives detailed illustrations of typical municipal drinking water and wastewater treatment plants and the processes they use.
Home purification systems may also be costly and confusing for homeowners who may not match the right kind of purification to the type of water they have.