What is Added to Purified Water? The Process and Benefits of Remineralization

December 12, 2025 •

4 min read

According to the World Health Organization, consuming demineralized or low-mineral water compromises the body's mineral and water metabolism. After being stripped of nearly all its content through purification methods like reverse osmosis, water often has essential minerals added back in, a process called remineralization. This process is crucial for restoring not only the health benefits but also the taste of the water.

Quick Summary

Purified water, stripped of minerals during filtration, is remineralized to restore essential electrolytes like calcium, magnesium, and potassium. This process is necessary for optimal hydration, better taste, and preventing potential health issues associated with demineralized water.

Key Points

Remineralization is the final stage of purification: After filtering out contaminants, essential minerals are added back to water.
Purification methods strip beneficial minerals: Processes like reverse osmosis and distillation remove healthy minerals along with impurities.
Key minerals added include calcium, magnesium, and potassium: These electrolytes are crucial for bodily functions like hydration, bone health, and nerve function.
Remineralization improves taste: Adding minerals back to purified water enhances its flavor, which can otherwise be flat or bland.
Long-term demineralized water consumption has risks: The World Health Organization has cited potential health concerns from drinking water with a very low mineral content.
Built-in remineralization is most convenient: RO systems with a post-filter remineralization cartridge are the easiest way to ensure balanced, mineralized water.
Minerals can protect against toxicity: Adequate levels of calcium and magnesium in water can help mitigate the risk of toxic metal absorption from plumbing.
Dietary intake may not fully compensate for lost minerals: While food is a primary source of minerals, water can play an important supplementary role, especially for minerals that are more easily absorbed from water.

Why Is Remineralization Necessary for Purified Water?

Water purification methods, while effective at removing harmful contaminants, can also strip water of naturally occurring, beneficial minerals. This is especially true for systems using reverse osmosis (RO) or distillation, which remove nearly everything, including Total Dissolved Solids (TDS). The resulting demineralized water, essentially pure H2O, lacks the electrolytes our bodies need and can taste flat or bland.

Remineralization is the process of reintroducing these essential minerals back into the water after purification. It is a critical step for improving not only the water's taste but also its health-promoting properties. The World Health Organization has noted that water with a TDS below 100 mg/L may have negative health implications due to its lack of minerals.

The Most Common Minerals Added to Purified Water

Several key minerals are typically added back to purified water to enhance its quality and health profile. These include:

Calcium: A vital mineral for strong bones and teeth, calcium also plays a role in nerve function and muscle contraction. It is often added in the form of calcium carbonate or calcium chloride.
Magnesium: Essential for over 300 enzymatic reactions in the body, magnesium supports muscle and nerve function, regulates blood pressure, and aids bone health. Magnesium is frequently added as magnesium sulfate or magnesium chloride.
Potassium: This electrolyte is crucial for maintaining fluid balance, regulating blood pressure, and ensuring proper heart and muscle function. Potassium bicarbonate is a common additive.
Sodium: Needed in small amounts to help regulate fluid balance and nerve function, sodium chloride is a common additive to improve taste.
Other trace minerals: Some water manufacturers and home systems add trace amounts of other minerals, but calcium, magnesium, and potassium are the most significant for health and taste.

How Minerals are Added Back to Purified Water

For commercially bottled purified water, companies use specialized filters or cartridges to reintroduce minerals. For home water systems, several methods exist:

Remineralizing Water Filters: These are often post-filters in a multi-stage system (like an RO system) that add a balanced blend of minerals back into the water just before it's dispensed. They contain mineral-rich media, such as magnesium phosphate and calcium carbonate, which dissolve into the water as it passes through.
Mineral Drops: Concentrated drops of trace minerals can be added manually to a glass or pitcher of purified water. While convenient, the mineral content can be inconsistent and may not fully replicate the balanced profile of naturally mineralized water.
Alkaline Water Pitchers: These use special filter cartridges that contain mineral balls to increase the water's pH and add back minerals like calcium and magnesium. However, they may not provide sufficient remineralization for water that has been thoroughly stripped by RO or distillation.
Himalayan Salt: Some people add a pinch of Himalayan salt to water, but this method is ineffective for proper remineralization. It adds an excessive amount of sodium compared to other essential minerals, potentially disrupting the body's electrolyte balance and exceeding health guidelines.

A Comparison of Water Remineralization Methods


Feature	Remineralizing Filter (Built-in or Add-on)	Mineral Drops	Alkaline Water Pitcher	Himalayan Salt
Convenience	Most convenient, automatic integration.	Requires manual addition to every serving.	Requires manual refilling of pitcher.	Requires manual addition and mixing.
Mineral Balance	Provides a balanced, consistent mineral profile.	Can be inconsistent; mineral type and dosage vary.	Primarily adds calcium and magnesium, with varying effectiveness.	Imbalanced, adds excessive sodium with minimal other minerals.
Cost	Upfront cost for filter, ongoing replacement cost.	Low monthly cost per bottle, but can add up.	Low upfront cost, regular filter replacement cost.	Very inexpensive, but not recommended for remineralization.
Best For	Full-scale remineralization for drinking, cooking, etc..	Occasional use for personal drinking water.	Increasing pH and minor mineral addition.	Primarily flavoring, not effective for health-based remineralization.

Potential Health Effects of Demineralized Water

Long-term consumption of purified water without remineralization can potentially lead to health issues. Aggressive, demineralized water can leach toxic metals from pipes, such as lead and cadmium, leading to potential health risks. Furthermore, the lack of essential minerals in the water means the body must work harder to maintain its mineral balance. This can be exacerbated if a person’s diet is also low in these nutrients.

Symptoms and conditions potentially associated with long-term demineralized water intake include:

Electrolyte imbalance, leading to fatigue, weakness, and headaches.
Increased risk of cardiovascular disease.
Changes in mineral metabolism, especially for calcium and magnesium.
Potential issues with gastrointestinal function.

While minerals in water are not the sole source of a person's daily intake, they can significantly contribute, and their absence can be detrimental, especially for those with already low dietary intake. For this reason, remineralizing purified water is often recommended.

Conclusion: The Final Step in Making Water Truly Healthy

While purification is an essential first step for removing harmful substances, it is only part of the process for creating truly healthy drinking water. Remineralization is the vital final step that restores the essential electrolytes and minerals stripped away by advanced filtration. Whether through built-in filters in a home RO system, mineral drops, or commercially bottled remineralized water, replenishing minerals like calcium, magnesium, and potassium ensures that the water not only tastes better but also supports the body’s metabolic functions and overall hydration. It transforms purely filtered water into a balanced and beneficial source of daily hydration.

Frequently Asked Questions

Advanced filtration systems like reverse osmosis (RO) are designed to remove virtually all dissolved solids and contaminants. While effective for purification, they cannot differentiate between harmful contaminants and beneficial minerals, so both are removed in the process.

While it can be safe in the short term, long-term consumption of demineralized water is associated with potential health risks, including mineral deficiencies and electrolyte imbalances. The World Health Organization recommends a minimum mineral content in drinking water.

The main purpose of remineralization is to restore essential electrolytes for health and to improve the taste, which can be described as flat or bland in demineralized water.

For comprehensive and consistent remineralization, a reverse osmosis system with a dedicated remineralization cartridge is the most effective method. Mineral drops offer a simple manual alternative for individual glasses.

No, adding Himalayan salt is not an effective method for proper remineralization. It adds an imbalanced and often excessive amount of sodium and does not replenish other vital minerals like calcium and magnesium in a healthful ratio.

Calcium, magnesium, and potassium are the most important minerals to add back, as they are crucial for fluid balance, nerve function, and bone health. Many water systems use compounds like calcium carbonate and magnesium sulfate to achieve this.

Yes, water that has been purified by methods that remove minerals, like reverse osmosis or distillation, often has a slightly acidic pH because minerals that buffer pH have been removed. Remineralization can help balance this by adding alkaline minerals.