How does Water Distillation Work? A Detailed Explanation with Graphics.

You may have come across bottles of distilled water in stores and wondered, “What’s with the expensive price tag?”

What exactly makes distilled water more costly and better than regular water?

Well, distillation is one of the oldest water purification techniques. We have included a step-by-step explanation of how this water distillation system works along with its advantages and disadvantages. We have even included some frequently asked questions to quench your curiosity.

So, let’s dive right into it!

What is Distillation?

Distillation is the process that involves boiling water and condensing it to produce pure water. This process allows for all the heavier contaminants to stay behind and removes harmful bacteria and viruses from your water as well.

Distillation is one of the most effective methods of water purification. Distilled water can be useful for drinking, cleaning, cooking, as well as other applications.

How Long has Water Distillation been Around?

Distillation has been around for a long long time. It can be traced back to nearly 200 AD. Since the principle is simple and based on the natural water cycle, it did not require too many materials to implement the system. Originally, distillation was used to distill salt from seawater.

However, this process was slow and proved to be expensive to run on a larger scale. This was until the invention of Kleinschmidt Still during World War II. This invention allowed distillation to become affordable and efficient. These days technology has allowed us to use flash-type evaporators for distilling seawater.

What does Water Distillation Remove?

Water Distillation is a process that boasts of removing up to 99.5% of the impurities from your water supply. It is best suited for removing heavier contaminants. It is also effective at removing soluble minerals such as calcium, magnesium, and phosphorus.

Similarly, water distillation is excellent at removing heavy metals such as lead, mercury, fluoride, and arsenic. Arsenic contamination is a big problem in countries like Bangladesh. The presence of lead or arsenic in your water supply can cause you to experience stomach pain, vomiting, diarrhea, and also put you at high risk for kidney failure.

In terms of organic waste, it can remove nitrates, bacteria, as well as a large number of dissolved solids. It is also effective against most pesticides and herbicides. This is why distillation is usually the go-to method of filtration for most people.

However, no method can provide you with 100% purified water. Likewise, distillation cannot remove volatile organic compounds from your water. Some of these organic compounds might actually become more concentrated due to distillation.

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How does Water Distillation Work?

During distillation, water moves through the states of matter. It needs to go from liquid to vapor and from vapor back to pure water. This entire distillation process can be summed up in about three simple steps.

Step 1: Boiling

Boiling is a straightforward process. The contaminated water is put into a container and then subjected to heat. The boiling point of water is 100 °C or 212 °F. At this temperature, the untreated water will begin to evaporate.

The boiling process is very effective at killing off a multitude of harmful microorganisms present in the water. Since the boiling point of water is relatively low when compared to the contaminants, it allows for water to evaporate faster. This ensures that only the contaminants are left behind in the original container.

Step 2: Condensation

Once the steam rises up in the container, we make sure that it travels via a tube. As the steam travels through this tube, it is cooled down. This process is very similar to how we get rain from the natural water cycle.

Cooling the water allows it to turn back from vapor into water droplets. These droplets are free from any of the heavy or soluble impurities. The condenser is usually a stainless steel coil tube. In large-scale distillations, a high-powered fan is equipped to speed up the cooling process.

Step 3: Collection

Once the water condenses, the droplets of water form pure water. In most commercial distillations, there is a carbon postfilter added. This is to ensure that any volatile organic compounds or impurities that may have escaped during the distillation process, can be removed as well.

How long does Water Distillation Take?

The length of time it takes for water distillation depends on the amount of water that needs to be distilled as well as the efficiency of the distiller. In general, a countertop water distiller takes about 4-6 hours to supply one gallon of distilled water.

Industrial grade water distillers, however, can shorten this to producing nearly 2-3 gallons of water within an hour. Furthermore, these are automatic so will require no interference from you other than emptying out the reservoir when full.

Types of Water Distillers

Water distillation is a process that is used widely across many fields. As such, there are different types of water distillers to suit these varied functions. The three major types of water distillers are explained as follows:

Household Distillers

This is the most common type of water distiller. Countertop distillers fall under this category. These distillers are very easy to use and will only need you to pour water into the system.

Plumbing Distillers

These are the slightly more advanced type of distillers. Instead of having to fill water into it, these are connected directly into your plumbing system. Plumbing distillers are generally more expensive and will also incur some installation costs. However, these are generally more cost-efficient in the long-run as they will provide you with distilled water as and when.

Commercial Distillers

These are the industrial-grade distillers that perform large-scale distillations. Equipped with high-speed cooling fans, these are able to produce pure water at much larger volumes. They are capable of producing millions of gallons of distilled water every day. These systems utilize multiple containers and simultaneously boil and condense large quantities of water.

Advantages of Water Distillation

This water purification system has been around for centuries. Some of these advantages are described as follows:

Highly Purified Water

Distillation is one of the most effective methods of water purification. It leaves your water free from most bacteria and viruses. Similarly, whether it is dissolved salts, solids, or metals, you can rely on distillation to remove it all. Especially when distillation comes with an additional filter to take care of all the impurities that are initially missed.

Variety of Uses

Distilled water is firstly an excellent choice for drinking water. It is widely used in many household applications such as cooking, cleaning and so on. Since it is free of most bacteria, it is also a great choice for humidifiers.

Using this pure water while making baby formula or food for sick people will ensure that you don’t worsen their condition. As this water doesn’t leave any residue it will be great for cleaning windows or any other surfaces.

Easy Installation

Usually, water purification systems require a great deal of professional installation. However, with water distillation, there is no need to mess with your plumbing system. All you need to do is get a countertop water distiller. Then, you plug it in and fill water into the boiling chamber. The distiller will take care of the rest.

In case you’d like the entire process to be automated, you will need to connect the distiller to a water source. But despite this, the plumbing changes required are minimal and easy to install.

Economical Investment

If you have browsed the various water distillation systems, you might have been initially scared off by the large price tags. When you’re used to tap water, it is easy to wonder if a distillation system is really worth the expense.

The thing to consider here is the long-term return value. Producing your own clean, distilled water will save you a lot more money over buying bottled water. Additionally, these distillers come with nearly 10 years of rated usage. This high usage can be lengthened via proper maintenance. Therefore, while the initial cost might seem steep, this system is guaranteed to be serving you faithfully for many years.

Disadvantages of Water Distillation

Even the best systems are bound to have some flaws. Similarly, some of the disadvantages of water distillation are listed as follows:

Energy Expenditure

Since your water distillation system runs on electricity, there might be a significant increase in your electricity expenditure. Boiling and cooling water continuously is a draining process and will cause a rise in your electricity bill. This is usually a major concern among people looking to purchase a distillation system.

However, if you take into account a comparison across the price of buying bottled water and the minimal rise in your energy bill, the choice is clear. Owning a water distiller will still be cheaper in the long run. For better energy expenditure, you should try to get a water distiller that can produce water quickly and more efficiently.


Since distilled water is boiled heavily, it lowers the oxygen content in the water. This water is also free from mineral impurities such as calcium and magnesium. Without these, your water is likely to taste quite flat.

Slow Production

As mentioned above, the distillation process does take some time. The condensed water turns back to pure water one droplet at a time. This time consumption means that this purification process is not suitable for you if you are in need of instant clean water.

The alternative to this is to install an automatic distillation system. This allows your water distiller to keep clean water ready for you throughout the day.

Frequently Asked Questions

There isn’t really one water purification system that is better than the other. Distilled water gets rid of most of the impurities and provides you with additive-free water. Similarly, RO water is free from 99% of the impurities, including the volatile organic compounds that distillation misses. However, distillation has a higher efficiency against microorganisms. Both systems have their pros and cons, it depends on which impurities you need to target.

Distillation is definitely one of the best ways to purify water. However, it comes with drawbacks such as expensive installation and slow production of pure water. These drawbacks make this purification process unsuitable for many applications.

Yes! You can drink distilled water as it is free from most impurities. However, you might then lack some of the necessary mineral impurities that is eliminated by the distillation process. You can still make up for this by eating a well-balanced diet. Furthermore, a lack of oxygen can make this water taste flat which may not be up to everyone’s tastes.

Distilled water is generally more expensive due to the costs involved in equipment and installation. This process also uses a lot of energy which may result in high prices.

In Summary,

Water distillation is a process that mimics the water cycle of the Earth. Water goes through boiling and condensation to produce clean water free from most soluble and insoluble contaminants. It is most effective at removing heavy impurities as well as impurities with a higher boiling point than that of water. 

The drawback is that it uses a lot of energy and can be expensive. However, it has been practiced for generations due to its high effectiveness.