What is Demineralized Water?

For anyone looking for the cleanest, purest drinking water, demineralized water can seem like the answer.

As the name suggests, demineralized water is a type of high-purity water that has had the majority of its dissolved solids  removed. But not all demineralized water sources are equal – it just depends upon the particular process that is utilized for purification. 

In this guide, I’ll be offering info on the different demineralization processes, the uses of demineralized water, whether you can drink demineralized water, and more.

What is Demineralized Water Used For?

There are several small- and large-scale uses of demineralized water. Some of the most common applications are as follows:

1. For Drinking

When it comes to drinking demineralized water, you’re best opting for distilled water or reverse osmosis water.

Water that has been distilled has had a near 100% removal of contaminants, while water processed or filtered by  reverse osmosis  has had, as a general rule, and depending upon which contaminants are present, 90%  of  contaminants removed.  These may include trace metals and mineral ions, to pathogens like bacteria, chemicals like chlorine, and suspended solids. 

This makes water much safer and healthier for drinking than your average tap water source. It’s important to keep in mind, however, that you may want to consider remineralizing ultra-pure water with healthy minerals before consumption.

2. For Manufacturing

Products that require water, such as cosmetics, aren’t manufactured using normal tap water. It’s important that pure water is used, which won’t react with the product’s other ingredients or add any unwanted impurities into the product.

Lipsticks, perfumes, body lotions and toothpastes are all examples of products that are manufactured with demineralized water.

3. To Prevent System Overheating

Additionally, demineralized water can be used in  power production, chemical production, manufacturing, or factory settings, to more efficiently cool systems, reducing overheating and helping  to maintain  optimum temperatures.

4. For Laboratory Use

Laboratories  utilize purified water as a control for testing, diluting and preparing solutions.

Purified water must be used in place of normal tap water as it helps scientists to ensure that data obtained is accurate, won’t create residue, and helps to maintain the integrity of experiments by preventing the introduction of contaminants or impurities which would compromise the results.

5. For Automotive Purposes

The automotive industry relies on demineralized or deionized water for a number of applications, including in gas-turbine engines, lead-acid batteries, and car cooling systems. However, professionals have to be careful with how and where they use demineralized water, as it can be more aggressive towards some metals and other materials.

6. For At-Home Use

You can use deionized water, the most commonly available type of demineralized water, in applications around the home, including as a cleaner, to fill steam irons, and for fish tanks.

Because deionized water has had its minerals removed, it’s particularly ideal for cleaning as it won’t leave behind any residue.

demineralized water for cleaning

How is Water Demineralized?

There are several different  processes that can remove minerals from drinking water, with the most popular being reverse osmosis, distillation, ion exchange and oxidation.

Reverse Osmosis

Reverse osmosis is one of the most economical residential filtration methods, and is used to purify drinking water with a point-of-use under-sink or countertop unit.

In most residential  RO systems, water flows  through a pre-filter, a carbon filter, a semipermeable membrane, and a post-filter. Each  stage of treatment removes contaminants of varying sizes and types, including minerals and salts, resulting in high-quality pure water. In larger commercial or industrial units, water pressure is raised before entering the membrane element to increase quantity and quality even further. 

An RO purification unit can be  somewhat  costly, averaging around $500-$1,000  with installation, but the quality of the treated water makes the initial investment  worthwhile.

Something to keep in mind with RO systems is that you’ll be required to change the filters (usually after 6-12 months for the pre, post, and carbon filters, and every 2+ years for the semipermeable membrane), so this isn’t a completely maintenance-free option. Also keep in mind that NO water treatment method is completely maintenance free.

reverse osmosis system for home


Another point-of-use at-home option to consider is distillation, which uses a countertop unit to produce distilled water. Distilled water contains no minerals and salts – and is free from practically all other existing impurities, too.

As with RO, the distillation process is quite thorough, with the boiling method being incredibly effective at removing contaminants.

To operate a distiller, you simply add water (H2O) to the boiling chamber, where it  will evaporate into steam before condensing back into pure water in a separate container. Contaminants like bacteria and lead, minerals like calcium and magnesium, and salts such as sodium are all left behind in the boiling chamber, as they’re unable to evaporate and condense with (H2O) particles.

You can find a good distiller for around half the price of an RO unit, and it requires virtually no maintenance to operate (just cleaning). However, it’s worth being aware that the distillation process is incredibly slow – it takes around 4 hours for 1 gallon of water to be produced by these systems- but as long as you stick to a schedule, you should always have access to clean water.

countertop water distiller

Ion Exchange

Ion exchange resins can also be used to remove minerals from water. These resins are known for their ability to soften water (i.e. reduce hardness minerals to less than 1 grain per gallon or 17.1 p.p.m. ) in a process that replaces minerals with other dissolved ions.

In a typical ion exchange unit, water flows through a cationic exchange resin, before flowing through an anionic exchange resin. The cationic exchange resin converts mineral ions into acids, and this acidic water then passes through the anionic exchange resin, which exchanges the water’s anions for ions in the resin bed (usually sodium particles).

Ion exchange is a highly effective method of demineralization and can produce water that’s free of cations and anions, thus removing its conductivity.

Deionization water softeners are usually on the costlier side, however, and can be priced at more than $1000. Typically, these systems are installed for whole-home benefits at a property’s point of entry.

springwell salt-based water softener system

Related: What’s the difference between reverse osmosis and water softeners?


Finally,  oxidation filters provide a form of purification  by removing a specific set of dissolved minerals. These filters can typically remove iron, but they may also remove manganese and sulfur.

In the oxidation process, water containing certain problem mineral ions is exposed to a filter media, typically greensand or a similar material, which has a manganese dioxide coating.

Being exposed to this media causes the mineral ions to convert into an insoluble form, where they can be flushed out of the unit when the media becomes saturated with particles.

While the oxidation method of purification is relatively effective, the process doesn’t remove all minerals. However, it’s a great option if you’re on a budget, as many oxidation filters are on the market at a much broader price range.

oxidizing media water filter for iron

Frequently Asked Questions

Is Demineralized Water the Same As Distilled Water?

Distilled water is an example of a particular type of demineralized water. Demineralized water is a term used broadly to describe a solution that has had its minerals, such as calcium and magnesium, removed. Distilled water is one of the purest demineralized drinking water options available, as it has a very low impurity content as well as containing no minerals.

Can You Buy Demineralized Water?

Yes, you can buy water that has had its minerals removed using one of the demineralization methods above.

Typically, deionized water is the cheapest and most available to buy. If you search online, you should also find distilled water for a relatively affordable price. Water that has been demineralized using RO, oxidation or ion exchange methods might be hard to come by, so if you’re particularly interested in a certain process, you should consider buying a filter unit for your home.

Of course, it’s worth considering why you actually want to use water that has been demineralized. If you don’t plan to drink it, you don’t need to worry so much about making sure it’s completely pure. It depends on what application you wish to use it in.

Can I Drink Demineralized Water?

Yes, you can, but some methods are better than others. Water that has been produced by an ionizer may have a negative impact on your health if you drink it exclusively, so this water is typically used for industrial purposes.

Distilled water and RO water pose less of a health risk, but emerging evidence from a WHO report suggests that water with a low mineral content may have unwanted health effects in the body.

If you enjoy the idea of drinking purified water but want to avoid these negative health ramifications, I would advise purchasing a remineralization filter to add as a final stage to your RO unit, or adding mineral drops to water that has been produced by a distiller. This will make your water generally healthier andsafer to drink.

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