What is a Water Distiller and How Does It Work?

Posted by
John Woodard on October 15, 2019

A water distiller turns water into steam to remove fluoride, arsenic, lead, viruses, and other contaminants. Water distillers produce water of unrivaled purity by imitating the Earth’s natural purification process. Available in compact countertop units and large automatic systems, water distillers provide your household with crystal clear water for drinking, cooking, and a host of household uses. Water distillers are able to clarify virtually all contaminants through a process of boiling and condensation, even difficult to remove contaminants like dissolved salts and solids. Not only are water distillers an environmentally friendly alternative to bottled water, they are also a much cheaper option and provide you with purified water in the comfort of your own home. 

What is a water distiller? 

A water distiller is a water treatment method that produces contaminant-free water by converting water into vapor before condensing it and returning it to a liquid state. During the evaporation process, impurities like bacteria, heavy metals, and arsenic are eliminated because they are unable to turn into steam. As the water transitions from a liquid to a gaseous state, these contaminants are left behind in the boiling chamber. The distiller then cools the evaporated water, returning it to its liquid state as a mineral-free, highly pure water. 

Water distillation mimics the way the Earth naturally purifies and redistributes water. The heat emanating from the sun evaporates water from the ocean and surface waters like lakes and ponds, turning it into water vapor. The water vapor rises and begins to cool. The cooling vapor condenses and creates clouds, before returning the water to the earth through precipitation like rain, snow, and hail. 

The hydrologic cycle is not only perpetually transforming the Earth’s water’s material form, the cycle is also recycling and purifying the Earth’s water. When the sun’s heat evaporates water, any contaminants or minerals present in the water dissipates. The salt present in briny ocean water is unable to become a gas, so, evaporated ocean water is salt-free. Everything from chemical waste to pathogenic microorganisms is left behind as the hydrogen and oxygen molecules transition from liquid to gas. The hydrologic cycle removes all the alkalinity and mineral content the water takes on when as it journeys through layers of rock and sediment. This is why when water rainwater falls to the Earth it is soft and slightly acidic. Distillation emulates the natural purification process in its production of exceptionally pure water. 

Earth Water Cycle Water Distiller Cycle

How does a water distiller work? 

    1. The water distiller boils the water, turning it into steam.
    2. The steam is then condensed and cooled, returning it back to a liquid state.
    3. Anything that cannot turn into steam, like minerals and microorganisms, is left behind.

To begin the process of distillation, water is poured into the boiling chamber. The boiling chamber is equipped with a heating element which will raise the temperature of the water to a rolling boil. As the temperature of the water elevates, steam is produced. The top of the boiling chamber is vented, and the rising steam travels through the vent into a condenser, leaving behind everything from bacteria to fluoride. The condenser is a stainless steel coil of tube where the vapor will be converted back to a liquid state. 

A high-powered fan at the top of the distiller chills the vapor, forming water droplets. These droplets then travel down the condenser tube and pass through an activated carbon postfilter. This is because there are some contaminants, like VOCs, that can exist in a gaseous state and may have escaped into the condenser alongside the steam. The activated carbon, through adsorption, eliminates any contaminants that may still be hanging onto the water droplets. The water droplets then exit the distiller and collect within a glass bottle or stainless steel reservoir.

How long does it take to distill water? 

It takes around 4-6 hours for a countertop water distiller to produce one gallon of distilled water. Like most high purity water filtration methods, the process of water distillation is a slow one. The water distiller produces purified water one droplet at a time. Over the course of several hours, the water distillers will produce enough droplets to fill up the reservoir with purified water. 

Larger, industrial-grade distillers are capable of producing water much faster. These units can produce anywhere from 2-3 gallons of distilled water per hour. While a standard countertop water distiller is designed to produce a single gallon of distilled water at a time, larger distillers have reservoirs as large as 12 gallons. These distillers are usually automatic, and will continuously replenish their reservoirs with distilled water as you deplete the stored supply. These distillers can even be plumbed to run distilled water to your ice maker or kitchen faucet if you desire. 

What does a water distiller remove? 

A water distiller removes fluoride, organic compounds, dissolved salts and solids, lead and other heavy metals, and almost all other impurities from water. By converting water into steam, a water distiller is able to discard all contaminants from the water it’s purifying. Viruses are neutralized during the boiling process, as pathogenic bacteria and potentially dangerous microorganisms are unable to withstand such high temperatures. Chlorine and chloramine are added by municipalities for sterilization purposes, but chlorine gives the water a chemical taste and odor. These are easily eliminated by water distillation. Contaminants like nitrates, pharmaceuticals, barium, copper, arsenic, and iron are all separated from your water by a water distiller. Water hardness is totally removed during the distillation process, as well as mineral content of any kind.

Contaminants that can convert to gas, notably VOCs and benzene, are caught by the activated carbon postfilter. If your distiller does not come with a carbon postfilter, like some larger automatic models, it is advised to install an inline prefilter to target these contaminants. These volatile organic compounds are carbon-based and they will adhere to the porous carbon surface area. Its removal of virtually all compounds and contaminants makes water distillation is one of the most comprehensive and exhaustive water filtration methods on the market. 

what a water distiller removes

Does boiling water distill it? 

No, merely boiling water will not produce the same high purity water achieved by water distillation. Boiling water is a great method of reducing harmful pathogens that may be present in the water. This is why when water pipelines become compromised or natural disasters damage city water systems, municipalities will issue boil water advisories. Boiling water is effective at eliminating bacteria, cysts, and protozoa because these microorganisms are unable to survive at such high temperatures. However, any chemicals, heavy metals, and dissolved solids present in the water will be unaffected. 

What are the advantages of a water distiller?

  • Guaranteed water purity: Distilled water is completely free of all bacteria, viruses, and inorganic compounds, protecting your body from a broad range of potentially harmful water contaminants. From dissolved salts and solids to metals leached from old pipelines to organic waste, contaminants are unable to survive the comprehensive distillation process. There are few water filtration or treatment systems available that are capable of delivering total contaminant reduction. A water distiller provides you with superior water purity in the comfort of your own home or office. 
  • Wide range of use: Distilled water can be used for a vast array of applications. Far from being limited to just drinking and cooking, distilled water is recommended for use in household products like irons and humidifiers. Preparing baby formula with distilled water alleviates any fear of bacteria creeping into your infant’s fragile immune system. Cleaning windows and surfaces with distilled water eliminates frustrating streaks and blurry glass. A water distiller provides you with pure water with a multitude of uses. 
  • Zero installation: Unlike other high purity water filtration systems, like deionization and reverse osmosis, a water distiller requires no lengthy and involved installation. All you need to do to set up your countertop unit is merely plug it into an electrical source. After that, just fill the boiling chamber and let the distiller purify your water. Automatic units do need to be connected to a water source so they can continuously provide you with purified water, but, this is a simple plumbing connection to make. Compared to the installation process that goes into even basic under-sink systems, water distillers are easily some of the most simple water treatment systems to install. 
  • Return on investment: Water distillers are some of the more expensive units to purchase initially, but they provide an enormous return on investment. Producing your own distilled water at home is far cheaper than purchasing bottled distilled water. Not to mention, bottled water is environmentally unfriendly and a poor substitute for an actual filtration system. A well-maintained water distiller will last at least 10-15 years, and the carbon postfilter replacements are quite inexpensive. 

What are the disadvantages of a water distiller? 

Every water treatment system has its respective advantages and disadvantages. Water distillers produce water of unparalleled purity, but there are some trade-offs to achieving these results.  

  • High electrical output: Water distillers do consume a significant amount of energy. They use a heating element to boil water and cool water over the course of hours. This tends to be most customer’s biggest trepidation when considering purchasing a water distiller. Water distillers are not energy efficient, and they will moderately increase your energy bill, depending on the volume of water you are distilling a day. However, to put the electrical cost into perspective, consider the savings you will accrue from forgoing bottled distilled water. Based on average household energy costs, you will spend about 30 cents distilling one gallon of distilled water. (It takes about 3 kilowatts to make one gallon, and a kilowatt of energy usually costs about 10 cents.) Purchasing a gallon of distilled water a grocery store will cost at minimum $2-3. So, though you are using more energy, it still cheaper than purchasing wasteful bottled water. Furthermore, systems capable of producing water faster than 1 gallon per hour will be more efficient. 
  • Flat taste: It’s true, distilled water does have a bit of a flat taste to it. This is because a water distiller is low in oxygen. Mineral content can also flavor to water, which is also eliminated during distillation. If you are unable to abide the taste of distilled water, then that may be a reason to find an alternative water filtration method. 
  • Slow rate of production: As previously stated, the process of water distillation takes considerable time. A water distiller clarifies water drop by drop, so if you’re in a rush to procure filtered water, you may be frustrated by the pace of distillers. However, most systems that produce water of such high purity operate quite slowly, like reverse osmosis. Such thorough purification of water cannot be achieved instantaneously. Investing in an automatic water distiller will ensure that water distillation is always in production, even when you deplete some of the reservoir. You can also run the distiller throughout the day, even when you don’t need water, and store the distilled water in pitchers or glassware in your refrigerator. This way, your access to distilled water will not be impeded by the speed of the system. 

Water distiller maintenance 

To keep your water distiller operating effectively, you will need to periodically clean the boiling chamber. During the distillation process, many of the eliminated contaminants will remain in the boiling chamber. Over time, hardness minerals like calcium and magnesium can cause limescale build-up in the chamber, damaging your water distiller and diminishing its performance. Regular cleaning will also preclude any bacterial or algae growth, and prevent mold from setting in. In addition to cleaning, rinsing your water distiller’s boiling chamber in between cycles can help keep the system clean. 

How to clean your water distiller:

    1. Turn off the distiller and remove the lid of the boiling chamber. If your distiller has a removable lid, detach it from the water distiller. Fill your sink with warm water and add in 1/4 a cup of white vinegar. You can also use lemon or lime juice, sulfamic acid, or a water distiller descaler like Still Clean
    2. Submerge the lid in the water. Allow the lid to soak in the solution for a few hours. If you cannot remove the lid, take a brush or cloth that’s been soaked in the cleaning solution and scrub the lid. 
    3. Pour a solution of 1/2 vinegar and 1/2 water into the boiling chamber. The white vinegar will loosen the pesky scale deposits forming on the inside of the boiling chamber. Be sure that your solution is several inches higher than the visible scale formations to ensure they will be removed. 
    4. Allow the solution to sit in the distiller overnight. Allow 12 hours for the solution to work its magic on your distiller. You may want to gently swirl the water around in the distiller, making sure all limescale deposits make contact with the vinegar solution. 
    5. Empty the water distiller and rinse. In the morning, pour the solution down the drain and fill the distiller with water. Thoroughly rinse out the distiller with warm water from your tap several times. 
    6. Allow the water distiller to air dry before reuse. After you’ve cleaned it, allow the system to dry out before plugging it back into a power source. Attach the lid back to the distiller, and you’re ready to produce your next batch of high purity water. 

Water distiller myths

When it comes to distilled water, there is no shortage of controversy, the majority of stemming from a lack of substantial research on the long-term health effects of drinking distilled water. Despite this, there are some common myths regarding water distillers that are worth discussing and dispelling. 

Does drinking distilled water deprive your body of minerals? 

Drinking distilled water does not deprive your body of minerals. Water does not possess a significant amount of mineral content and your body does not rely on water for its nutrient intake. Water dissolves the minerals you consume through fruits and vegetables and delivers them to your internal organs and bones. Water itself does not furnish your body with nutrition. The claim that distilled water will lead to mineral deprivation implies that the body depends on water to supply it with minerals, and this is simply untrue. To quote the World Health Organization, “In general, drinking water has not been relied upon as a contributor of significant trace nutrients to daily intake, but rather as a serendipitous supplement whenever it occurs.” You should be consuming minerals like calcium, magnesium, potassium, and iron through your diet or through vitamins and supplements. Any minerals your body gets from water should be considered an added bonus. Water performs many vital bodily functions, but it is not a source of nutrients. 

If you do desire minerality in your distilled water, mineral water supplements are readily accessible online. These will add trace minerals back into your water, boost the pH, and add a fresh alkaline taste. These inexpensive supplements come as liquid solutions, and adding just a few drops in your water distiller’s collection jug will relieve any fears you have of drinking mineral-free water.   

Is drinking distilled water bad for you? 

Drinking distilled water is not bad for you. The water distillation produces water of remarkable purity, and though it is completely mineral-free, it is not harmful for you. If you are malnourished or suffering from an illness, your body needs all the mineral content you can provide it, so distilled water may not be the best choice in those instances. Distillation does remove electrolytes from the water. Electrolytes are minerals that facilitate hydration during periods of intense physical activity. If you are exercising or exerting great physical effort, your body will be more sated by mineral water. However, barring those circumstances, there is no reason to be concerned about drinking distilled water. 

Clean, high-quality water is vital to staying healthy. Water hydrates and lubricates our bodies so that we function properly. Our bodies are 70-80% water, so it is important to be sure that the water we consume remains high-quality so that organs like our kidneys do not over-work themselves to filter out unnecessary solids.

Learn more about the safety and health effects of drinking distilled water.

What is distilled water used for? 

Distilled water’s exceptional purity makes it ideal for use in a wide array of medical, industrial, scientific and household applications. Its total lack of contamination is perfect for use as a coolant for engines, sterilization for equipment like sump pumps, and water for humidifiers and Neti-pots. Distilled water also enhances the performance of lead-acid batteries, as well as prolongs their lifespan. In fact, many manufacturers recommend exclusively using distilled water in their appliances to preserve the longevity and efficiency of their products. 

Distilled water for car batteries and radiators

Distilled water promotes electrical flow in lead-acid car batteries. As the battery recharges, electricity passes through the water, breaking it down on a molecular level and converting it into hydrogen and oxygen gas. Over time, this process will deplete the levels of water within the lead-acid battery. Tap water contains traces of minerals, which can lead to limescale build-up and corrosion inside the battery. This will prematurely destroy the battery, making it vital to only add mineral-free distilled water when replenishing the battery’s water supply. Neglecting to water your lead acid battery leads to a condition known as sulfation. Sulfates crystals will begin to accumulate on the battery’s plates, leading to diminished battery performance, longer charging times, and ultimately battery failure. 

Distilled water is also perfect for dilution of the coolant for your car’s radiator. When mineralized water is added to a radiator, it will corrode the interior, leading the radiator to consume exorbitant energy. The strain this puts on the radiator will reduce its lifespan, incurring a costly and avoidable replacement. 

Distilled water for CPAP machines and humidifiers

A Continuous Positive Airway Pressure (CPAP) machine is one of the common treatment therapies for people suffering from sleep apnea. Sleep apnea is a sleep disorder that causes people to stop breathing while they’re asleep. CPAP machines apply constant air pressure to a person’s lungs via a mask, keeping a person’s airways open and inducing breathing throughout sleep. CPAP machines have a humidification chamber to keep the air moist, to prevent sinuses from drying out and staving off colds. It is vital to only use distilled water in the CPAP’s humidification chamber. Inhalation of bacteria, ammonia, and chlorine from tap water can cause infections and compromised immune systems. Using only distilled water will prevent any mineral build-up or bacterial growth from setting in the humidification chamber.

Similarly, distilled water is recommended exclusively for the use of humidifiers. Like CPAP machines, humidifiers deliver increased humidity in your home by releasing moisture into the air. These machines moisturize your throat and nasal passages, improving sinus and allergy inflammations and assist you in overcoming colds. Using heavily chlorinated water in a humidifier can cause respiratory irritation. Bacterial growth within the humidifier can present unsanitary conditions that lead to airborne contaminant exposure that will worsen medical conditions. To maintain the cleanliness of the humidifier and protect your health, only use distilled water in humidifiers. 

Distilled water for Neti pots 

Neti pots, a popular nasal irrigation method where a saline solution is used to flush a clogged nasal passage, are used by many people to alleviate congestion. However, after highly publicized stories emerged linking brain-eating amoebas with Neti pot usage, these ceramic pots have come under intense scrutiny. Used with distilled water, Neti pots are entirely safe and practical ways to relieve sinus congestion. This is because distilled water is 99% free of contaminants, ensuring bacteria will not enter into your body. It is also strongly encouraged you regularly clean your Neti pot with distilled water, to ensure the interior is sterile. 

Distilled water for home use and appliances 

Distilled water can be used for a wide variety of household appliances and cleaning tasks. For example, using distilled water in your iron prevents any minerals from creating a scale build-up that can ruin the appliance. As any aquarium owner knows, fish are extremely sensitive to chemicals like chlorine or any bacterial presence. Using distilled water to fill your aquarium provides you with neutral, purified water free from any contaminants that could harm your fish. Once you remineralize it, it creates a safe and healthy environment for your fish to thrive in.

Distilled water is also a fantastic cleaning agent. Your tap water can possess minerals that can cause soap scum build-up and leave unappealing streaks on your windows and computer monitors. These white stains are the results of dissolved salts and minerals in your water that prevent cleaning products from properly lathering and can leave an unsightly residue. Cleaning with distilled water gives you brighter, clearer windows and shinier sinks. Many people even use distilled water as a final rinse on their car after washing it, as it flushes away mineral content that leaves water spots and can damage the paint job. 

Distilled water for the medical and scientific industry

In an industry where sterilization is of the utmost importance, it is unsurprising that distilled water is the standard for medical procedures. Surgeons use distilled water to wash wounds, sterilize surgical instruments, and clean hospital equipment. Distilled water’s unmatched purity lends itself to the rigorous sanitary conditions the medical industry requires to promote patient safety. 

Most laboratories utilize distilled water for experiments and cleanliness. Even filtered water can contain trace compounds of minerals or metals that could disrupt scientific findings. Distilled water is free of chemicals and bacteria, ensuring experiments produce accurate, unadulterated results. Distilled water can also be used for hydroponic systems, as hydroponic growing requires minute control over the nutrients and minerals supplied to the plants. Distillation allows the grower to start with a blank slate, adding in an exact mixture of nutrients to promote plant growth. 

Can a water distiller be used to distill alcohol? 

A water distiller can be used to distill alcohol; however, it is illegal unless you have a permit to do so. If you would like to distill alcohol, you will need to apply for a Federal Distilled Spirits Permit and research your local state laws regarding alcohol distillation. 

Water distiller alternatives 

If you are interested in acquiring a high purity water treatment system, but aren’t sure that a water distiller is the correct choice for you, there are alternatives worth exploring. Though distilled water is generally considered to boast the greatest contaminant reduction claims out of all water filtration systems, there are other methods of producing purified water. 

Reverse Osmosis Systems 

Like water distillers, reverse osmosis systems produce water of exceptional purity. By forcing water through a semipermeable membrane, reverse osmosis units separate contaminants, dissolved solids and salts, and minerals from water. The reverse osmosis membrane can reject over 96% of all dissolved particulate matter from water. From arsenic and lead to fluoride and cysts, reverse osmosis is a water distiller’s closest competitor when it comes to water purity. 

Reverse osmosis (RO) units are usually installed under-sink as point-of-use systems. Unlike distillers, they are plumbed directly to a dedicated faucet at your kitchen sink, where they will dispense crystal clear water. Like distillers, reverse osmosis works very slowly. Water travels through the infinitesimal pores on the reverse osmosis membrane and collects in a storage tank beneath your sink. However, reverse osmosis will continue to fill the tank with purified water until tank capacity is reached and the system will shut off. You do not have to manually load the water as you do for countertop water distillers, and you can purchase storage tanks that will hold much greater than just one or two gallons. Though automatic water distillers will also continuously produce distilled water as the reservoir is depleted, they are significantly more expensive than a reverse osmosis system. 

Another advantageous element of reverse osmosis is the option to add in a remineralizing cartridge. These remineralizers can be installed inline after the membrane and will dissolve calcium carbonate and magnesium dioxide into the water. This gives the water a refreshing alkaline taste, returns mineral content to the purified water, and also raises the pH of the water. This 

The greatest disadvantage to reverse osmosis the amount of wastewater the filtration method generates. A water distiller thoroughly purifies water drop-by-drop, depositing all of it in the collection chamber without any waste. Reverse osmosis will send around 80% of all the water it processes to the drain. An RO system creates two streams during the filtration process, separating the purified water from the contaminated water. The solution of rejected contaminants, called brine, is discharged from the system as wastewater through a drain tube. To increase your reverse osmosis’s efficiency, select a system with a permeate pump. A permeate pump can be used to mitigate the amount of waste produced by reverse osmosis, reducing the amount of waste created by 75-80%. 

Learn more about how reverse osmosis works. | Explore 5 of our favorite reverse osmosis systems


  • High purity water without high energy costs 
  • Quicker and more convenient access to purified water 
  • Remineralizing cartridges can raise the water’s alkalinity and mineral content 


  • A significant amount of wastewater is generated
  • More complex installation and maintenance process 

Ultrafiltration systems

Ultrafiltration systems are another under-sink water filtration system with an impressive contaminant reduction list. Like reverse osmosis, ultrafiltration uses membrane technology to reduce contaminants from your drinking water. Utilizing a hollow fiber membrane with an expansive surface area and a .02 micron rating, ultrafiltration deftly eliminates impurities like lead, pesticides, and viruses. 

However, ultrafiltration cannot reduce as many contaminants as water distillers or reverse osmosis. Total dissolved solids (TDS) passes through the hollow fiber membrane, as does arsenic, fluoride, and dissolved salts. If you are seeking a system that offers total reduction of waterborne contaminants, an ultrafiltration system is not the most optimal system for your home. However, this degree of contaminant reduction is not always necessary or preferred. 

One of ultrafiltration’s greatest strengths is its ability to operate effortlessly at even moderate household water pressures. Ultrafiltration filters water on-demand, so you do not have to wait for a lengthy distillation process to transpire or for your storage tank to fill up. Ultrafiltration systems are inexpensive, relatively simple to install, and do not have as many components as a reverse osmosis system. 


  • Filters a gallon of water per minute
  • Operates smoothly under low water pressure
  • No wastewater generated
  • Does not remove minerals 


  • Cannot purify water as extensively as a water distiller or an RO system
  • Expensive filter replacements

Learn more about how ultrafiltration membranes work. | Explore reverse osmosis vs. ultrafiltration.

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