The question of which brand of bottled water is the healthiest does not have a single, simple answer. The concept of “healthy water” depends on a balance of two primary factors: its safety and purity, and its beneficial mineral composition. Understanding the source and treatment process of the water is far more relevant than focusing on a specific brand name. Ultimately, the healthiest choice is water that is free of contaminants and provides a desirable level of naturally occurring compounds.
Defining the Differences in Water Sources
Purified water, a common bottled product, can originate from any source, including municipal tap water or groundwater. This water undergoes extensive processing, such as reverse osmosis, deionization, or distillation, to remove nearly all dissolved solids and impurities. The rigorous process leaves the water exceptionally clean, but it also strips away naturally occurring minerals.
Spring water must be collected from an underground formation where water flows naturally to the surface. It is often filtered to remove particulates and may be disinfected, but the processing is intentionally minimal to preserve its original composition. The mineral content of spring water can vary significantly depending on the geology of its source.
Mineral water is defined by its consistent level and proportion of naturally occurring minerals and trace elements. To earn this designation, the water must contain at least 250 parts per million (ppm) of Total Dissolved Solids (TDS) that originate from the source. Unlike other types, nothing can be added to mineral water to increase the TDS level.
Tap water, or municipal water, is sourced from surface or groundwater and is treated by local authorities using processes like filtration, coagulation, and disinfection, often with chlorine or chloramine. It is typically fluoridated to support dental health. The level of minerals in tap water, which contributes to its “hardness,” is highly variable depending on the local watershed.
Essential Mineral Content and pH
The concentration of dissolved substances in water is measured by Total Dissolved Solids (TDS), which includes inorganic salts and trace organic matter. TDS is a practical measure for consumers because it directly influences taste and indicates the presence of beneficial minerals. Water with very low TDS, such as purified water, may taste “flat” because the flavor compounds have been removed.
The World Health Organization (WHO) suggests that water with a TDS level between 300 and 600 ppm is generally considered good, while levels below 300 ppm are excellent. Conversely, water with excessively high TDS, often above 1,000 ppm, may be unpalatable due to a salty or metallic taste. The absence of TDS, however, also means the absence of nutritional contribution.
Two of the most relevant minerals found in water are calcium and magnesium, both of which are readily absorbed by the body from drinking water. Magnesium supports muscle function, energy production, and a steady heart rhythm. Calcium is necessary for strong bones, nerve signaling, and blood clotting.
While water is not the primary source of these nutrients for most people, a mineral-rich water can contribute meaningfully to daily intake, especially for individuals whose diets may be low in these elements. Studies have shown an inverse association between magnesium levels in drinking water and the risk of cardiovascular mortality. The benefits are tied to the presence of these compounds.
Another common consideration is the water’s pH level, which determines if it is acidic (below 7) or alkaline (above 7). The human body maintains a tightly controlled blood pH level around 7.4 through biological mechanisms like respiration and kidney function. Drinking alkaline water does not significantly change the body’s systemic pH.
Although some research suggests that highly alkaline water (pH 8.8) may help neutralize the stomach enzyme pepsin, offering relief for individuals with acid reflux disease, the scientific evidence for broad health benefits remains mixed and inconclusive. Any perceived health benefit from alkaline bottled water may be linked to the trace minerals, such as calcium and magnesium, that are often present or added to achieve the higher pH.
Understanding Quality and Safety Standards
The safety of water is governed by two different federal bodies, creating a distinction in regulatory oversight. Municipal tap water is regulated by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act (SDWA). This regulation requires public water systems to test for contaminants frequently, sometimes multiple times a day, and mandates public reporting of test results and any violations.
Bottled water, on the other hand, is regulated by the Food and Drug Administration (FDA) as a packaged food product. While the FDA requires bottled water standards to be at least as stringent as the EPA’s public water standards, the frequency of testing and the requirement for public reporting are typically less strict. This difference means consumers often have less access to current quality reports for bottled water compared to local tap water.
A growing concern for both types of water is the presence of microplastics, which are tiny plastic fragments that enter the environment from various sources. Multiple studies have indicated that bottled water generally contains significantly higher levels of microplastics than municipal tap water. This contamination is thought to stem from the plastic bottle itself, especially as the plastic degrades over time or when exposed to heat.
For a consumer, the choice comes down to balancing safety assurance with desired mineral content. Highly regulated municipal tap water offers transparent, frequent testing data for safety. Mineral-rich bottled water provides beneficial compounds like calcium and magnesium, but with less public transparency regarding its testing schedule. Therefore, the “healthiest” water source is the one that reliably meets high purity standards while offering an appreciable level of beneficial minerals.