Can you drink ion exchange water?

November 26, 2025 •

4 min read

While many people believe softened water is unsafe to drink due to myths, millions worldwide consume it without documented harm. This article clarifies if you can drink ion exchange water, detailing the different types and what you need to consider regarding your health and the water's composition.

Quick Summary

Ion exchange water's safety depends on its processing. Softened water, which replaces calcium and magnesium with sodium, is generally safe. Deionized water, which removes all ions, lacks minerals and can be corrosive, making it unsuitable for drinking.

Key Points

Softened Water is Generally Safe: Water from an ion exchange softener removes hardness minerals (calcium and magnesium) by replacing them with a small, typically insignificant amount of sodium, and is safe for most healthy individuals.
Deionized Water is Not for Drinking: The deionization process removes nearly all ions, including beneficial minerals, and can be corrosive to pipes. It is primarily used for industrial applications, not for regular human consumption.
Minimal Sodium Concern: The added sodium in softened water is minimal and not a concern for the average person, although those on strict low-sodium diets should exercise caution.
Distilled vs. Deionized: Both lack minerals, but deionization does not remove uncharged pathogens like viruses or bacteria, which can be a risk if the source water is not pre-treated.
Supplement for Enhanced Purity: Combining a water softener (for whole-house hard water issues) with a separate drinking water filter, such as a reverse osmosis system, offers the benefits of both soft water and high-purity drinking water.
Consideration for Infants and Health Conditions: Due to sodium levels, softened water is not recommended for preparing infant formula, and those with specific health concerns should consult a physician.

Understanding Ion Exchange Water

Ion exchange is a chemical water treatment process that removes undesirable dissolved ions by swapping them with other ions. The process uses synthetic resin beads that are specially formulated to attract and bind specific ions from the water. This fundamental principle is applied in several different ways, resulting in various types of ion exchange water, with the most common being water softening and deionization.

Water Softening: Replacing Hard Minerals

Water softeners use ion exchange resin to remove 'hardness' minerals, primarily calcium and and magnesium, which cause scale buildup in pipes and appliances. As hard water passes through the resin bed, the calcium and magnesium ions are captured and replaced with tiny amounts of sodium ions. The amount of sodium added is usually minimal and depends on the initial hardness of the water. This process results in what is commonly called 'softened water'.

Deionization: Removing All Ions

Deionized (DI) water, or demineralized water, is created by running water through both a cation (positive ion) and an anion (negative ion) exchange resin. The cation resin replaces positive ions with hydrogen (H+), while the anion resin replaces negative ions with hydroxyl (OH-). The hydrogen and hydroxyl then combine to form pure H2O. The goal of deionization is to produce water that is nearly free of all ions, which is ideal for laboratories and manufacturing processes but has distinct implications for drinking.

Can You Drink Softened Water?

For the vast majority of healthy individuals, softened water is perfectly safe to drink.

Sodium Content: The primary concern with softened water is the added sodium. However, the amount of sodium is generally not significant for most people. For example, a glass of softened water adds only a small fraction to the daily recommended sodium intake. The taste change is often negligible, though some with highly sensitive palates may notice a slight difference.
Mineral Balance: While softened water removes calcium and magnesium, these minerals are most effectively absorbed from food rather than water. The body gets the vast majority of its essential minerals from a balanced diet, so their absence in softened water is not a health concern for most people.
Special Populations: Individuals on very strict, low-sodium diets for conditions like high blood pressure or kidney disease should consult a doctor before drinking softened water. Parents of infants may also prefer to use non-softened water for formula, as recommended by some health authorities.

Why Deionized Water is Not Recommended for Drinking

Unlike softened water, deionized water is not recommended for regular human consumption for several key reasons.

Lacks Essential Minerals: The complete removal of beneficial minerals like calcium and magnesium means DI water offers no nutritional value. Regular consumption can potentially lead to mineral imbalances over the long term.
Corrosive Nature: Water that is completely free of ions is highly aggressive and seeks to dissolve minerals it comes into contact with. This means it can leach toxic metals like lead from older pipes and storage containers.
Potential for Contaminants: The deionization process removes ions but does not remove uncharged organic compounds, including some bacteria and viruses. DI water is often made from a pre-filtered municipal source, but it is not sterile unless additional purification steps are taken.
Flat Taste: The absence of minerals in DI water leaves it with a notably flat or unappealing taste, which can make it less thirst-quenching.

Comparison: Ion Exchange vs. Other Water Types


Feature	Ion Exchange (Softened)	Ion Exchange (Deionized)	Distilled Water	Tap Water	Reverse Osmosis Water
Process	Ion exchange removes Ca²⁺ and Mg²⁺, adds Na⁺	Ion exchange removes all cations/anions	Boiling and condensing water	Municipal treatment	Semi-permeable membrane filtration
Mineral Content	Low in Ca²⁺/Mg²⁺, higher in Na⁺	Extremely low, nearly zero	Extremely low, nearly zero	Varies; contains minerals	Low, but varies
Effect on Taste	Often described as smoother or slightly sweeter	Flat and unappealing	Flat and unappealing	Varies based on source	Generally clean taste
Safety for Drinking	Generally safe for most	Not recommended for regular consumption	Safe for consumption, but lacks minerals	Varies; generally safe but may contain contaminants	Very safe; removes many contaminants
Primary Use	Household appliances, drinking, cleaning	Labs, electronics manufacturing	CPAP machines, irons, car batteries	Everyday drinking, cooking, household	Home drinking water filtration

The Verdict: Drinking Ion Exchange Water

The suitability of drinking ion exchange water depends entirely on the type. Water from a household softener is safe for most people, while laboratory-grade deionized water is not meant for human consumption. If your primary concern is mineral hardness, a water softener is a simple and effective solution. For comprehensive contaminant removal and improved taste, combining ion exchange (for hard water) with a separate purification system, like reverse osmosis, for drinking water is a popular strategy. Always consider your personal health and dietary needs when choosing your drinking water source.

Conclusion

In summary, the question of "can you drink ion exchange water?" has a nuanced answer. The ion exchange used in water softening results in a product that is safe and refreshing for most people, with minimal impacts on health or sodium intake. However, deionization, the process used to create DI water, removes essential minerals and can be corrosive, making it unsuitable for drinking water. Understanding the specific type of ion exchange process is crucial for making an informed choice for your home and health. Consulting a water professional can help determine the best filtration system for your specific needs, ensuring both safety and quality. For an in-depth look at water treatment systems, visit the Water Technologies Handbook.

Frequently Asked Questions

Softened water, a common type of ion exchange water, often tastes smoother or slightly sweeter due to the removal of hard minerals. Deionized water, however, is typically described as having a flat or unappealing taste because it lacks all minerals.

For most people, the trace amounts of sodium added during the ion exchange softening process are not harmful. The level is generally too low to impact health, though individuals with high blood pressure or other sodium-sensitive conditions should consult their doctor.

No. The human body primarily absorbs essential minerals like calcium and magnesium from food, not water. Drinking softened water will not cause a significant mineral deficiency for most people with a balanced diet.

No, you should not use deionized water for baby formula. The World Health Organization and other health bodies caution against using demineralized water for infants, and the complete lack of minerals can upset a baby's mineral balance.

Deionized water is 'hungry' for ions because they have been removed. When it comes into contact with materials, such as old pipes, it will leach ions and toxic metals from them to reach equilibrium, making it corrosive.

No. The standard ion exchange process only removes charged ions, not uncharged pathogens like bacteria and viruses. For this reason, deionized water is often pre-treated or paired with other purification methods.

Softened water is a specific type of ion exchange where only hard minerals like calcium and magnesium are swapped for sodium. Deionized water is a more aggressive form of ion exchange that removes nearly all ions, leaving the water without any mineral content.