What is the cleanest, purest bottled water? Your definitive guide

According to the World Health Organization, while bottled water is regulated, its safety and purity can vary significantly between brands, with some even containing trace contaminants. To find out what is the cleanest, purest bottled water, it's essential to understand the science behind purification and how different types of bottled water are processed.

Quick Summary

This guide explains the different types of bottled water and their purification processes, revealing which methods produce the purest water. It compares distilled, purified, spring, and mineral water, covering their pros and cons. Key factors affecting purity, including contamination risks, filtration techniques, and regulatory standards, are also addressed.

Key Points

• Distilled Water is Purest: Distillation removes nearly 100% of all dissolved solids, making it technically the purest form of bottled water, but it often lacks flavor.

• Purified Water is a Strong Compromise: Many brands use reverse osmosis (RO) to create purified water, which offers high cleanliness and may have minerals added for better taste.

• Source Doesn't Guarantee Purity: Natural spring and mineral waters can contain varying levels of minerals and other dissolved solids, and their cleanliness depends on the source and processing.

• Look Beyond Marketing: Brands are regulated by agencies like the FDA in the U.S., but consumers should check labels for specific purification methods and be wary of claims that are mostly marketing.

• Packaging Matters: Plastic bottles can leach contaminants like microplastics, especially when heated. Aluminum or glass are safer packaging choices.

• Independent Testing is Key: Reports from organizations like Consumer Reports have found contaminants like PFAS in some bottled water brands, highlighting the need for vigilance.

Defining "Clean" and "Pure"

When searching for the cleanest, purest bottled water, it is important to first understand what these terms mean in a scientific context. The term "purest" generally refers to water with the lowest possible amount of total dissolved solids (TDS), including minerals, chemicals, and other contaminants. Distilled water is the gold standard for purity in this sense, as the distillation process removes nearly 100% of all impurities. "Cleanest" can be a more subjective term, often referring to water free from harmful contaminants while still retaining a desirable mineral profile for taste and health benefits. Most consumers desire a combination of both—a product that is free from contaminants but still pleasant to drink.

The Role of Purification Methods

Bottled water companies use a variety of treatment methods to achieve different levels of purity. Understanding these processes is key to choosing the right water for your needs.

Distillation

Distillation is one of the oldest and most effective purification methods. Water is boiled into steam, and the steam is then collected and condensed back into a liquid, leaving all dissolved minerals, contaminants, and bacteria behind.

Reverse Osmosis (RO)

Reverse osmosis forces water through a semi-permeable membrane at high pressure. This membrane has pores small enough to block dissolved solids, heavy metals, and microorganisms. Many major brands, such as Aquafina and Dasani, use RO to purify their water.

Filtration and Ozonation

Many spring and mineral water companies use less intensive methods. Filtration, often with carbon filters, removes larger particles and some organic compounds. Ozonation is a common disinfection method that uses ozone gas to kill bacteria and viruses before bottling.

Types of Bottled Water: Purity vs. Minerals

Not all bottled water is created equal. The type of water depends heavily on its source and the purification applied.

• Distilled Water: The highest purity level in terms of removed solids. Because the minerals are removed, it can taste "flat." It is excellent for use in appliances like humidifiers or CPAP machines but is not the most popular for everyday drinking.
• Purified Water: Often municipal tap water or groundwater that has been treated with processes like reverse osmosis or distillation. Manufacturers may add a mineral blend back in for taste, giving a low TDS but more palatable water. Brands like Aquafina and Smartwater are examples.
• Spring Water: Sourced from a natural underground spring and must be collected at the spring or through a borehole. It is naturally filtered by rock layers and contains a unique mineral profile from its source. Purity depends on the source and processing, but it is not completely free of dissolved solids. Fiji and Evian are well-known spring waters.
• Mineral Water: Sourced from a protected underground mineral spring and is characterized by a specific and stable mineral content. The US FDA requires a minimum of 250 parts per million of total dissolved solids (TDS) for water to be labeled as mineral water. It is not considered the "purest" but is valued for its taste and mineral content. Perrier and Acqua Panna are examples.
• Alkaline Water: Has a pH level higher than neutral water (pH 7). This can occur naturally (e.g., Icelandic Glacial) or be achieved through ionization and mineral additives. Its purity level depends on the source and initial filtration. While some favor its taste, its health benefits are not definitively proven.

How to Assess Bottled Water Quality

For the discerning consumer, here are some steps to take to evaluate the cleanliness of your bottled water:

Scrutinize the Label

Reading the label is your first line of defense. Look for information about the source (e.g., municipal, spring, artesian well) and the treatment process (e.g., reverse osmosis, distillation, ozonation). Brands that are transparent about their processes are often more trustworthy.

Understand Regulatory Oversight

In the U.S., the Food and Drug Administration (FDA) regulates bottled water as a food product and requires that its standards be at least as protective as the EPA's standards for tap water. Reputable brands often join industry associations and undergo third-party audits to ensure quality.

Consider the Packaging

Plastic bottles can leach microplastics and chemicals like antimony into water, especially when exposed to heat. Reusable glass, stainless steel, or aluminum containers are safer alternatives. Some brands like Pathwater use aluminum for this reason.

Comparison Table: Distillation vs. Reverse Osmosis

Factor	Distillation	Reverse Osmosis (RO)
Purity Level	Removes virtually all contaminants, including minerals, heavy metals, and bacteria.	Removes up to 99% of contaminants, including most dissolved solids and microorganisms.
Process	Water is boiled into vapor and condensed back into liquid, leaving impurities behind.	Water is forced through a semi-permeable membrane under pressure.
Energy Use	High energy consumption due to the boiling process.	Lower energy consumption, relying on pressure rather than heat.
Waste Byproduct	Minimal waste, primarily mineral residue left in the boiling chamber.	Produces a significant amount of wastewater, or brine, during filtration.
Final Taste	Often described as "flat" or tasteless due to the lack of minerals.	Can have a neutral, fresh taste, especially if minerals are added back post-filtration.
Best For	Labs, medical applications, and humidifiers where absolute mineral-free water is needed.	Home use, drinking water, and commercial applications where high purity and efficiency are required.

The Verdict: What Is The Cleanest, Purest Bottled Water?

For those prioritizing the removal of the absolute highest percentage of dissolved solids and contaminants, distilled water is technically the purest. However, its taste is often undesirable for drinking. Most consumers will find that purified water treated by reverse osmosis is the ideal balance of cleanliness and palatability. Brands like Aquafina and Smartwater use this method, often adding electrolytes back for improved taste. While spring and mineral waters offer unique mineral profiles from natural sources, their purity can vary and they are not as low in TDS as purified water. Ultimately, the cleanest, purest choice for daily drinking depends on a balance between your personal taste preferences and a desire for maximum contaminant removal. Always check for certifications and transparent labeling, and consider the environmental and health impacts of packaging, such as plastic vs. aluminum.

Conclusion

While the search for the single cleanest, purest bottled water is a nuanced one, the answer largely depends on your definition of "pure." If your goal is zero dissolved solids, distilled water is the answer. If you seek a balance of safety, taste, and mineral content, purified water processed by reverse osmosis is a popular and effective choice. Always research the brand's source and purification methods, and consider reputable brands that undergo rigorous testing. For consumers with concerns about municipal tap water, bottled water offers a reliable alternative, though considering home filtration or alternative packaging can mitigate some of the environmental and health risks associated with plastic.

For information on water quality testing and regulation, you can consult reputable sources like the International Bottled Water Association (IBWA).

Frequently Asked Questions

Which bottled water has the fewest impurities?

Distilled water has the fewest impurities because the distillation process involves boiling the water and collecting the condensed steam, leaving all minerals and contaminants behind.

Is purified or mineral water cleaner?

In terms of lacking dissolved solids, purified water is generally cleaner as it has undergone intensive filtration processes like reverse osmosis to remove impurities. Mineral water, by definition, contains a specific amount of naturally occurring minerals.

Do all bottled waters go through the same purification process?

No, purification processes vary. Distilled water is boiled, purified water often uses reverse osmosis and carbon filtration, while spring and mineral waters may only use light filtration and ozonation to preserve their natural mineral content.

Is bottled water regulated for safety?

Yes, in the U.S., bottled water is regulated as a food product by the FDA, with standards required to be at least as stringent as the EPA's for tap water.

What is the risk of drinking from plastic water bottles?

Plastic bottles can leach chemicals like antimony and microplastics into the water, particularly when exposed to heat. Reusing single-use bottles can exacerbate this issue.

Does distilled water taste different?

Yes, distilled water often has a "flat" or neutral taste because the distillation process removes all the minerals that contribute to water's flavor.

Should I be concerned about contaminants like PFAS in bottled water?

Some bottled waters have been found to contain detectable levels of contaminants like PFAS. Checking independent testing reports from organizations like Consumer Reports and choosing brands with strict quality control can help address this concern.