The main difference between purified water and distilled water is the concentration of minerals. Purified water typically contains trace amounts of calcium, magnesium, sodium, potassium, and chloride. Distilled water, on the other hand, is virtually free of all minerals.
Here is a comparison table highlighting the major differences between purified water and distilled water:
|Method of purification
|Filtration, reverse osmosis, carbon filtration, UV treatment, etc.
|Free from chemicals, impurities, and chemicals but may still contain trace minerals.
|Free from almost all impurities
|Slightly tasteful due to the presence of calcium, magnesium, and potassium minerals
|Flat taste or bland
|Drinking, cooking, coffee and tea brewing, and water dispensers.
|Laboratory experiments, medical procedures, cosmetics, humidifier and CPAP machines, and industrial applications requiring ultra-pure water.
|Typically ranges from around $0.50 to $3.00 per gallon (3.78 liters) depending on the brand or type of filtration system used.
|Typically ranges from around $0.25 to $1.00 per gallon (3.78 liters) depending on the brand or type of distiller used.
|Can be made at home through a filtration system and widely available in various brands and forms.
|Can be made at home through a water distiller system and is widely available in various brands and forms.
|Lower environmental impact than distilled water as it does not require energy to boil water.
|Higher environmental impact than purified water as it requires energy to boil water.
What is Purified Water?
Purified water is water that has been filtered or treated to remove impurities and contaminants. This can include physical, biological, and chemical contaminants, such as sediment, bacteria, viruses, pesticides, herbicides, pharmaceuticals, and heavy metals like iron, manganese, lead, and mercury. Purified water is mainly used for drinking, cooking, and other household purposes such as brewing coffee and tea, making clear ice cubes, and cleaning contact lenses.
Public water purification is a complex process that involves a variety of steps to remove impurities from water. The most common methods of public water purification include:
- Coagulation and flocculation: This is the first step in water purification. Coagulation is the process of adding positively charged chemicals or ions to the water to bind with negatively charged particles. This chemical interaction promotes the formation of larger particles called floc. Flocculation is the process of binding these clumps together, making them easier to separate from the water.
- Sedimentation: The water is then allowed to rest undisturbed in a large tank or basin. As the water remains still, gravity causes the heavier floc particles to settle down to the bottom of the tank, gradually accumulating and forming a sediment or sludge layer. The clarified water, which is now significantly cleaner, is carefully collected from the top of the tank or basin.
- Filtration: The clarified water is then filtered through a series of filters. These filters contain media such as gravel, sand, charcoal, and activated carbon, or membranes with tiny pores. The filtration process effectively removes suspended particles, microorganisms, and impurities like dust, bacteria, viruses, organic matter, pesticides, herbicides, and pharmaceuticals. The specific types of impurities that are removed will depend on the type and characteristics of the filters used.
- Chemical disinfection: The chemical disinfection step uses chemicals like chlorine to kill any bacteria, viruses, or parasites that may have survived the previous steps. Chlorine is the most common chemical used for disinfection, but other chemicals, such as ozone, can also be used.
Without public water purification before water reaches us, we won't be able to safely drink it from the tap.
In countries with unsafe tap water, such as Afghanistan, Angola, Bangladesh, Burkina Faso, Burundi, Cambodia, Central African Republic, Chad, Democratic Republic of the Congo, Eritrea, Ethiopia, Ghana, Haiti, India, Indonesia, Kenya, Liberia, Madagascar, Malawi, Mali, Mauritania, Mozambique, Nepal, Niger, Nigeria, Pakistan, Rwanda, Sierra Leone, Somalia, South Sudan, Sudan, Tanzania, Uganda, Yemen, purification is essential before you drink water. The same is true if you’re drinking water from a natural source, unless it’s spring water.
The United States Environmental Protection Agency (EPA) sets safe upper safety limits for contaminants in drinking water that must be adhered to the Safe Drinking Water Act (SDWA). For example, the EPA's limit for lead is 15 parts per billion (ppb). This means that no more than 15 ppb of lead can be present in drinking water, on average, over a lifetime.
The EPA upper limits must not be exceeded by any state, but some states have even more stringent rules about contaminants in drinking water. For example, California has a limit for arsenic 0.001 mg/L or 1 ppb that is 10 times lower than the EPA limit of 10 ppb. That means that, state to state, drinking water safety standards (and tap water quality) vary. For example, the average level of lead in tap water in New York City is 13 ppb, while the average level in Flint, Michigan is 15 ppb.
The difference in these two levels is significant, as lead can cause a number of health problems, including developmental delays in children.
It's important to note that even if a state's drinking water meets the EPA's standards, it won't be completely safe. This is because the EPA's standards are based on the amount of a contaminant that's considered to be safe for human consumption over a lifetime. However, some contaminants like lead, copper and nitrate can cause short-term health effects, even at levels below the EPA's limits.
Therefore, it's important to further filter your tap water, especially if you're concerned about the quality of your water supply.
How to Purify Water at Home
To purify water at home, there are four most common methods, including:
- Filtration: Water filtration involves passing the water through a physical barrier or filter media, such as activated carbon, sand, or membranes, to remove dissolved contaminants or particles. These contaminants may include bacteria, viruses, pesticides, herbicides, heavy metals like lead, mercury, cadmium, and arsenic, as well as chlorine, depending on the type of filter used at home. The most popular filters for home usage are activated carbon filters (35%), reverse osmosis systems (25%), whole-house filters (20%), pitcher filters (10%), countertop filters (5%), and showerhead filters (5%), according to the 2022 survey by Water Quality Association (WQA) that's titled as “2021 WQA Consumer Opinion Study”.
- Boiling: Boiling is the easiest and cheapest method of purifying water at home. The process of boiling involves heating water to its boiling point, which is 100°C or 212°F at sea level. At high altitudes, the boiling point of water is lower due to the lower atmospheric pressure. For example, at an altitude of 2,000 meters (6,600 feet), the boiling point of water is 93°C or 199°F. Boiling water for at least one minute is an effective way to kill bacteria, viruses, parasites, and other microorganisms.
- Chlorination: Chlorination is a chemical method of purifying water at home. It's mainly used to eliminate bacteria, viruses, and parasites from water. The two most common types of chlorine bleach used for water purification at home are sodium hypochlorite and calcium hypochlorite. These are available in liquid, tablet, and granular forms. The amount of chlorine bleach to add to the water depends on the level of contamination. Generally, it's recommended to add 1-2 tablespoons of chlorine bleach per 100 gallons (378.541 liters) of water. Liquid chlorine typically costs $1–$2 per gallon, tablets cost $0.50–$1 per tablet, and granules cost $1–$2 per ounce.
- Iodination: Iodionation is another chemical method of water purification that can be used at home. It's also used to kill bacteria, viruses, and parasites in the water. Generally, it's recommended to use 8 drops per gallon for low contamination, 16 drops per gallon for medium contamination, and 24 drops per gallon for high contamination. Iodine is typically more expensive than chlorine bleach. The liquid iodine costs $1–$2 per ounce, the tablets cost $0.50–$1 per tablet, and the granules cost $1–$2 per ounce.
What are the Benefits of Purified Water?
There are several benefits of purified water:
- Improved taste: Purified water contains a trace of minerals such as calcium, magnesium, and potassium which gives waste a clean and fresh taste and promotes better hydration.
- Reduced risk of waterborne diseases: Purified water is free from bacteria, viruses, parasites, and other microorganisms. This reduces the risk of developing waterborne diseases such as diarrhea, cholera, typhoid, amoebiasis, and hepatitis A. Unsafe water is a major cause of diarrheal diseases, which kill an estimated around 525,000 children under five each year, according to the WHO.
- Reduces risk of kidney stones: Kidney stones are formed when minerals in the urine crystallize and form solid masses. Purified water has a lower mineral content of calcium than tap water, which can help to reduce the risk of forming kidney stones.
- Good for water-based appliances: Purified water typically has a low level of calcium, iron, and sulfates, which can reduce the chances of mineral deposits and corrosion in water-based appliances such as dishwashers, coffee makers, irons, steamers, and water heaters. This can extend the lifespan of these appliances. A study by Wang, Bill B titled “Research on drinking water purification technologies for household use by reducing total dissolved solids (TDS).” found that water that contains ions and minerals can cause clogs and drains problems in water boilers, heaters, and plumbing pipes, which can reduce their lifespan.
- Improves skin health: Drinking plenty of water keeps your skin hydrated and may help prevent wrinkles. Purified water is a good choice because it's free from impurities that can cause skin irritation, as stated by the Mayo Clinic.
- Improves hair health: Purified water can be beneficial for hair health because it's free from impurities such as chlorine, hard water, and sulfates that can strip off natural oils from hair and keep the hair hydrated. This may help to prevent dryness, frizziness, and damaged hair.
What are the Downsides of Purified Water?
There are four potential drawbacks of purified water:
- Loss of beneficial minerals: Some filters and water treatments, such as reverse osmosis systems and water softeners can remove up to 95% of beneficial minerals in water, such as magnesium and calcium. These minerals are essential for bone health, muscle function, and nerve transmission. While these beneficial minerals can be reintroduced to RO-treated water, they may not be as readily digestible as in their natural form.
- Fluoride removal: Reverse osmosis, activated alumina, and ion-exchange filters can remove 95%, 85%, and 70% of fluoride from water, respectively. While water fluoridation reduces tooth decay by 20% to 40% according to The Journal of the American Dental Association (JADA), fluoride levels of more than 2 mg/L can cause cognitive impairment in children, according to the study “The Relationship between Fluoride Exposure and Cognitive Outcomes from Gestation to Adulthood: A Systematic Review” carried out by Gopu, Banu Preethi, et al. WHO recommends fluoride levels between 0.5 to 1.5 mg/L for safe drinking water.
- Initial cost and maintenance: The cost of water filtration systems can range from $50 to $5,000, depending on the type of filter and the features included. Pitcher filters are the most affordable option, costing around $50 to $100. Under-sink filters are more expensive, costing around $100 to $300. Whole-house filters are the most expensive option, costing around $300 to $5,000. In addition to the initial cost of the filter, some filters may require regular cartridge replacements. The frequency of replacement will depend on the type of water, the frequency of use, and the lifespan of the cartridge. For example, the average cost of a pitcher filter cartridge is $10 to $20, while the average cost of a whole-house filter cartridge is $50 to $100.
- Environmental impact: Reverse osmosis is one of the most common water purification methods, but it produces wastewater that harms the environment with pollutants like bacteria, viruses, and heavy metals. Generally, it generates up to 50% wastewater compared to incoming water volume. For instance, purifying 10 gallons will yield 5 gallons of purified water and 5 gallons of wastewater. Disposing of used filters in landfills further impacts soil, groundwater, and wildlife.
What is Distilled Water?
Distilled water is water that has been boiled and the resulting steam is then condensed back into liquid form. This process removes impurities and minerals from the water, leaving behind highly pure H₂O. Distilled water is the purest form of water available, and it's mainly used in applications where absolute purity is required, such as in laboratories and in the manufacturing of electronic devices.
Compared to other purification methods, such as reverse osmosis systems, ion exchange, or carbon filters, distillation provides the highest level of purity. In fact, according to Purdue University, distillation is effective in removing viruses, bacteria, protozoa like giardia, and various heavy metals and chemicals such as lead, iron, and sulfate.
Can You Make Distilled Water at Home?
Yes, you can make distilled water at home with just a few simple supplies. Here's what you'll need:
- A clean, heat-resistant glass bowl
- A deep pot
- Ice cubes or a cold pack
Here are instructions to distill water at home:
- Place the glass bowl in the pot.
- Fill the pot with water, leaving about an inch of space between the water level and the top of the bowl.
- Heat the pot on the stove until the water boils.
- Place the ice cubes or cold pack on top of the lid.
- Let the steam rise and contact the cold lid surface.
- As the steam cools, it will condense into water droplets on the lid's underside.
- The water droplets will fall into the glass bowl, collecting largely impurity-free distilled water.
- Once you have enough distilled water, carefully remove the lid and transfer the water to a clean container for use or storage.
That's it! You've now made distilled water at home.
Alternatively, you can purchase a water distillation system to produce relatively larger quantities of water in relatively less time and with a more efficient process. Water distillation systems work by heating water and directing the steam to cool in a secondary area, where it becomes distilled water, leaving behind almost all the impurities.
What are the Benefits of Distilled Water?
There are four main benefits of distilled water:
- Free from contaminants: Distilled water is free from contaminants, including potentially harmful chemicals, heavy metals, and other impurities. However, it also removes minerals and electrolytes that we need in our diets to stay healthy.
- Lifesaving: In emergency situations, when you don't have access to clean water, distilled water is a lifesaver. It can be used for drinking, cleaning wounds, and taking medications that require tablets or capsules to be dissolved in water.
- Beneficial for specific medical conditions: Distilled water can be beneficial for people with certain medical conditions that are affected by the levels of minerals in the water. For example, distilled water can help to reduce the amount of minerals that the kidneys have to filter in people with kidney disease, and it can help to lower the levels of uric acid in the blood in people with gout. Additionally, some people with irritable bowel syndrome (IBS) find that drinking distilled water helps to reduce gas and bloating.
What are the Downsides of Distilled Water?
These are four main drawbacks of distilled water:
- Lacks essential minerals: Distilled water lacks essential minerals, such as calcium, magnesium, sodium, potassium, and chloride. This can increase the risk of developing certain health problems, such as a deficiency in calcium can lead to bone loss, a deficiency in magnesium can lead to high blood pressure, heart disease, and diabetes, and a deficiency in potassium can lead to heart rhythm problems, according to the Harvard T.H. Chan School of Public Health.
- Tastes flat: Distilled water tastes flat or bland because it lacks the minerals and dissolved solids that give tap water its taste, such as calcium, magnesium, chloride, sulfate, bicarbonate, and carbon dioxide.
- Increases risks of certain diseases: Studies have shown that women (65 years of age or older) who drank water with low levels of calcium were more likely to have hip fractures than women who drank water with higher levels of calcium. (Study: “Calcium intake in elderly patients with hip fractures.” by Cho K, Cederholm T, Lökk J.). In addition, drinking water with low levels of magnesium has been linked to an increased risk of heart disease. (Study: “Demineralization of drinking water: Is it prudent?” by Verma, K C, and A S Kushwaha.)
- Can be corrosive: Distilled water is generally non-corrosive, but it can be corrosive to some materials, such as plastic and metals because it lacks the essential minerals such as calcium and magnesium that protect against corrosion.
- Expensive: Distilled water is generally sold for around $0.25 to $1.00 per gallon (3.78 liters) because it requires a lot of energy during the distillation process and has a lower demand than other types of water, making the prices higher. Additionally, it's typically sold in small bottles, which factors in increasing the prices per gallon.
What are the Applications of Distilled Home?
There are five main non-consumption uses of distilled water:
- Laboratories: Distilled water is ideal for preparing solutions for chemical reactions or lab experiments, as it will not interfere with the accuracy of results. It is also used to clean laboratory equipment, as it will not leave behind any residue that could contaminate future experiments.
- Medical settings: In medical settings, distilled water is used to sterilize medical equipment, such as needles and syringes, by removing any bacteria or microorganisms that may cause the spread of infections.
- Home appliances: Distilled water is mainly used in steam irons, humidifiers, and water kettles to prevent mineral build-up. Mineral build-up can cause these water-based appliances to malfunction, produce less steam, and have a shorter lifespan.
- Automobile batties and cooling systems: Distilled water is used in cars to top off batteries and flush cooling systems. It prevents the build-up of minerals and scale, which can damage batteries and reduce cooling system efficiency.
- Personal care products: Distilled water is used in personal care products because it's free of impurities, minerals, and contaminants. This makes it a good solvent for the active ingredients in these products. For example, distilled water is used in shampoos and conditioners to help dissolve the cleaning agents and conditioners. It is also used in lotions and makeup to help the products spread evenly and absorb into the skin.
Which Type of Water Should I Choose: Purified or Distilled?
Purified water is the gold standard for daily household needs such as drinking, cooking, and tea and coffee brewing because it provides a balance of safety and taste while retaining essential minerals that are good for your health. In the United States, tap water is already purified to meet safety standards set by the U.S. Environmental Protection Agency (EPA). However, additional filtration can further enhance its quality by removing potential contaminants and impurities.
Distilled water is so pure but not necessarily healthy. It's free of impurities, including bacteria, viruses, good minerals, and electrolytes. This makes it ideal for applications where purity is critical, such as in laboratories, medical settings, and automobile batteries. Distilled water is also safe to drink but it's not the best choice for everyday drinking as it lacks beneficial minerals, such as calcium, magnesium, potassium, and sodium, and electrolytes, which are essential for a variety of bodily functions, including maintaining blood pressure, regulating fluid balance, and supporting muscle and nerve function.