Is it unhealthy to drink purified water?

December 12, 2025 •

4 min read

Studies from the World Health Organization highlight that while effective in removing contaminants, reverse osmosis systems can eliminate 92-99% of essential minerals. This brings up an important question: is it unhealthy to drink purified water over the long term?

Quick Summary

Purified water, while safe, lacks essential minerals due to the purification process. Regular consumption may cause mineral deficiencies. This can be addressed through a balanced diet or re-mineralization.

Key Points

Mineral Depletion: Purification methods like reverse osmosis and distillation eliminate harmful contaminants but also eliminate beneficial minerals such as calcium and magnesium.
Risk of Deficiency: Regularly drinking demineralized water may lead to mineral deficiencies if these nutrients are not adequately replaced through diet.
Electrolyte Issues: A lack of minerals in purified water can affect electrolyte balance, which may lead to issues like muscle cramps and fatigue, particularly in athletes.
Better Alternatives: Mineral-rich spring water or re-mineralized purified water offer a balance of safety and nutritional benefits, or one can ensure a diet rich in mineral-dense foods.
Safety First: Purified water is a much safer choice than unfiltered tap water for individuals in areas with contaminated water, and any mineral concerns can be managed through diet.
Taste and Acidity: Purified water can taste flat and may be slightly acidic due to its low mineral content, while some mineral-rich water can have a distinct taste.

What is Purified Water?

Purified water undergoes a process designed to remove impurities and contaminants. The source of purified water is usually tap water, though other sources may be used. The aim of water purification is to ensure water is safe to drink by getting rid of potential threats like bacteria, viruses, heavy metals, and chemicals. Purified water differs from spring water, which keeps its natural mineral content, and filtered water, which may not remove as many impurities.

How is Water Purified?

Several common methods are used for water purification, and each has a different effect on the water's mineral content and purity.

Reverse Osmosis (RO): This process uses a semipermeable membrane to filter out contaminants at a molecular level. It is very effective but can remove many beneficial minerals.
Distillation: This method involves boiling water and then condensing the steam back into a liquid, leaving contaminants and minerals behind. Distilled water is the purest form of water, but it is completely demineralized.
Activated Carbon Filtration: Often used with other processes, this method absorbs impurities such as chlorine and volatile organic compounds (VOCs), improving the taste and smell of the water.
UV Sterilization: Ultraviolet light is used to inactivate or kill microorganisms like bacteria and viruses, but it does not remove chemical contaminants.

The Lack of Essential Minerals: The Main Concern

The major health concern about purified water is its lack of minerals, particularly calcium, magnesium, and potassium. These minerals play key roles in bodily functions, and their absence can have long-term effects if not supplemented through other dietary sources.

Calcium: Important for strong bones, teeth, and muscle function.
Magnesium: Supports muscle and nerve function, heart health, and helps regulate blood pressure and blood sugar.
Potassium: Helps regulate fluid balance and maintain healthy blood pressure.

Regularly drinking highly purified water, particularly from reverse osmosis or distillation, without a balanced diet full of minerals, could lead to mineral deficiency. For most healthy people with a balanced diet, the impact is small. However, groups such as athletes, who lose electrolytes through sweat, or those with existing health conditions need to be more careful about their mineral intake.

Purified Water vs. Mineral-Rich Water

Here is a comparison between purified water and mineral-rich water sources, such as spring water:


Feature	Purified Water	Mineral-Rich (Spring) Water
Purity	High purity, with up to 99% of contaminants removed.	Varies, with minimal filtration to remove harmful elements.
Mineral Content	Low to no mineral content, especially with RO or distillation.	Contains naturally occurring minerals like calcium, magnesium, and potassium.
Taste	Often described as neutral or 'flat' due to lack of minerals.	Varies in taste depending on the source's mineral composition.
Source	Can come from any source, including tap water.	Must originate from a natural underground spring.
Safety	Consistently safe, removing a wide range of contaminants, including chlorine and lead.	Generally safe, but natural sources can sometimes have trace amounts of contaminants.

The Importance of Balanced Hydration

While purified water is not inherently unhealthy, it is important to remember that hydration involves more than just water. It is about maintaining the body's overall balance, which includes electrolytes and minerals. For some, especially those living in areas with questionable tap water quality, purified water is a necessary and safer alternative. In these cases, it is important to ensure that essential minerals are obtained from other dietary sources.

Some water companies and home systems offer re-mineralization options, adding minerals back to the water after purification, to provide the best of both worlds. This can improve the water's taste and nutritional profile without adding contaminants.

Conclusion

Drinking purified water is a safe and effective way to avoid harmful contaminants found in some water sources. However, the long-term, exclusive consumption of demineralized water, without enough dietary supplementation, could lead to mineral deficiencies and potential health issues. This is not a major concern for most people with a balanced diet. People with specific health needs, high activity levels, or dietary restrictions may need to be more mindful of their mineral intake. The choice between purified and mineral-rich water depends on personal preference, local water quality, and dietary habits. It's often best to ensure safe, clean water while maintaining a healthy, mineral-rich diet or choosing a purified product that re-mineralizes the water post-filtration.

Navigating Your Water Choices

Consulting a healthcare professional about specific hydration needs is recommended for those still unsure. The quality of local tap water, your dietary habits, and personal health should all be considered when making your decision. Many find a home filtration system to be a cost-effective and environmentally friendly way to control water purity, compared to relying on bottled water. Remember, staying hydrated is the most important factor, regardless of your chosen water type.

The CDC offers comprehensive resources on drinking water safety.

Frequently Asked Questions

Regularly drinking purified water may contribute to mineral deficiencies because the purification process, especially reverse osmosis and distillation, removes beneficial minerals like calcium and magnesium. However, most people get the majority of their minerals from a balanced diet.

RO water is not inherently bad for you and is effective at removing contaminants. The main concern is that it also removes essential minerals. The World Health Organization has suggested that long-term intake may have adverse effects, but these can be addressed by ensuring adequate mineral intake from other sources.

Yes, for most people, the minerals needed for bodily function are primarily sourced from a balanced diet of fruits, vegetables, and other foods. Drinking purified water is safe as long as your diet provides sufficient minerals.

Whether purified water is better than tap water depends on the quality of your local tap water and your personal health concerns. Purified water offers a safer option by removing more contaminants than standard municipal treatment, providing peace of mind in areas with poor water quality. Tap water is often perfectly safe and regulated by the EPA in many countries.

Purified water often tastes different, or 'flat,' because the purification process removes the minerals and other dissolved solids that give natural water its characteristic flavor. Tap water, on the other hand, can have varying tastes due to its mineral content and disinfection chemicals like chlorine.

The main difference lies in the source and processing. Spring water comes from a natural underground source and retains its natural mineral content. Purified water can come from any source, including tap water, and is processed to remove nearly all impurities and minerals.

Individuals with existing mineral deficiencies, athletes who lose electrolytes through sweat, and those with poor or restricted diets should be cautious about relying solely on purified water. In these cases, ensuring mineral intake is vital.