Understanding Contamination in Bottled Water
Determining what is the least contaminated bottled water involves looking beyond marketing claims to the reality of how water is sourced, treated, and packaged. The journey from source to shelf can introduce various contaminants, which are not always disclosed to the public.
Source Water and Processing
The source of bottled water—whether it is spring, artesian, or municipal—is the first factor affecting its purity. Many popular brands simply bottle filtered municipal tap water, often treated with processes like reverse osmosis. While effective at removing many contaminants, this process also strips water of its natural minerals. Spring and artesian waters, like Mountain Valley Spring Water, are sourced from underground aquifers and naturally filter through rock, potentially picking up beneficial minerals along the way. However, even natural sources can be susceptible to environmental pollutants if not properly protected.
Packaging Materials
Another significant source of contamination comes from the packaging itself. Standard plastic (PET) bottles are a major contributor to microplastic particles found in water, particularly when exposed to heat or over time. The antimony catalyst used in PET manufacturing can also leach into the water. For this reason, many consumers concerned about purity opt for brands that use glass or aluminum packaging, which are non-reactive materials that do not shed plastic particles.
Key Contaminants to Watch For
Microplastics
Microplastics are tiny plastic particles found in the vast majority of bottled water brands, originating from the bottle and cap. A 2018 study found plastic particles in 93% of bottled water samples, with concentrations sometimes exceeding 10,000 particles per liter in a single bottle. Brands in glass or aluminum bottles naturally avoid this type of contamination.
PFAS (“Forever Chemicals”)
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals found in various industrial applications and are known for their persistence in the environment. Consumer Reports testing in 2020 detected measurable levels of PFAS in many popular bottled waters. While some brands showed levels below established safety guidelines, the widespread presence of these chemicals is a cause for concern.
Heavy Metals
Heavy metals like arsenic, lead, cadmium, and mercury can seep into water sources from the surrounding environment. Consumer Reports' testing revealed that some brands, like Starkey Spring Water, had detectable arsenic levels, though the company noted it was within federal safety limits. However, this underscores the importance of independent testing beyond minimal regulatory standards.
Comparing Bottled Water Purity: A Brand-by-Brand Look
| Brand | Source | Packaging | Microplastic Presence | PFAS Detected | Heavy Metals | Notes |
|---|---|---|---|---|---|---|
| Mountain Valley Spring Water | Natural Spring | Glass | Low to None | No | Free of Pb, Cd, Hg, As | High purity, glass bottles, low microplastic risk |
| Path Water | Spring Water | Aluminum | Low to None | Undetectable | Not specified | Aluminum container reduces plastic exposure |
| Tourmaline Spring | Sacred Living Water | Plastic | Not specified | Yes (>1 ppt) | Not specified | Higher PFAS than some competitors |
| Starkey Spring Water | Spring Water | Plastic | Not specified | Not specified | Yes (Arsenic) | Arsenic detected, though within federal limits |
| Aquafina | Municipal (RO) | Plastic | Yes | Undetectable | Not specified | Extensive RO purification but uses plastic bottles |
| Nestlé Pure Life | Municipal (RO) | Plastic | Yes | Yes | Not specified | High microplastic count reported in some tests |
| Icelandic Glacial Water | Spring Water | Plastic | Likely | Not specified | Naturally purified | Naturally high pH from lava rock filtration |
Note: This table is based on publicly available independent test data and company information. Purity can vary by batch and testing methodology. The Consumer Reports bottled water test provides a more comprehensive look at these issues, available at their website.
How to Find the Least Contaminated Water
To confidently find the cleanest bottled water, consider these steps:
- Choose glass or aluminum packaging: Switching to non-plastic packaging, such as glass or aluminum, is the most direct way to avoid microplastic and chemical leaching from PET bottles. Brands like Mountain Valley and Path Water are excellent choices.
- Review independent test results: Major bottled water brands are not required to disclose purity test results, so relying on independent organizations like Consumer Reports and the Environmental Working Group is critical.
- Consider the water type: While spring water is naturally sourced, purified water processed via reverse osmosis can offer a more consistently pure product by removing a wider range of contaminants. However, many brands add minerals back in for taste.
- Avoid prolonged heat exposure: Storing plastic bottled water in a hot car or in direct sunlight can accelerate the leaching of chemicals from the packaging into the water.
- Explore home filtration options: For the ultimate control over purity, a high-quality home filtration system (such as reverse osmosis or a robust carbon filter) can be a more sustainable and potentially purer alternative to bottled water.
Conclusion
While marketing for bottled water often paints a picture of ultimate purity, independent testing reveals a more complex reality involving microplastics, PFAS, and heavy metals. For those seeking the absolute least contaminated bottled water, options packaged in glass or aluminum, such as Mountain Valley Spring Water or Path Water, consistently score high on independent purity tests by minimizing plastic-related contaminants. By staying informed and choosing brands based on test results rather than just brand recognition, consumers can make a cleaner, healthier choice for their hydration needs. Opting for non-plastic packaging is the single most effective step to avoid common bottled water contaminants.
