Despite the convenience of bottled water and its frequent appearance in scenes of people consuming it on television programs or commercials, experts say that this product is not as pure as advertised or as imagined by people. It is also not necessarily cleaner than the tap water in most developed countries. Given the conditions permit, it is still advisable to drink tap water.
Professor Muhammad Wakil Shahzad, an expert in advanced energy and sustainable development in the Mechanical Engineering Department at Northumbria University in the United Kingdom, wrote in an article on The Conversation website that marketing has positioned bottled water as purer, healthier, and more convenient, but scientific evidence reveals a different truth.
The perceived purity of bottled water is the key factor attracting consumers, but studies have shown that bottled water itself can bring about a series of health and environmental risks.
Shahzad wrote that a study published in 2025 revealed that bottled water may not be as safe as many people believe. Testing conducted on water contained in reusable water bottles and plastic bottles showed that these waters were contaminated with high concentrations of bacteria.
Previous studies have also indicated that bottled water contains various pollutants, including plastic particles, chemical residues, and bacteria. A study published in 2024 detected tens of thousands of plastic particles per liter in certain products.
In most developed countries, tap water regulations and testing standards are more stringent than those for bottled water. Public water supply systems undergo daily testing for bacteria, heavy metals, and pesticides.
For example, in the United States, water companies must comply with the National Primary Drinking Water Regulations regulated by the Environmental Protection Agency (EPA). In Europe, tap water quality is governed by the European Drinking Water Directive.
In comparison, bottled water is regulated as a packaged food product. Its testing frequency is lower, and manufacturers are not required to disclose detailed quality information.
In addition to potential chemical pollutants in the water, chemicals such as antimony, phthalates, and bisphenol analogs can leach from bottled water bottles. Antimony is a catalyst in the production of PET (polyethylene terephthalate) bottles, which are the most commonly used plastic for single-use beverage containers. Phthalates are plasticizers that maintain the flexibility of plastic.
Bisphenol analogs (such as BPS or BPF) are closely related to BPA. BPA is a chemical used to harden certain plastics and line food and beverage cans. These substances can migrate into water, especially when bottles are stored in warm environments like cars, trucks, or direct sunlight.
Scientists are concerned because some of these compounds may interfere with the human hormonal system. Prolonged exposure to certain phthalates and bisphenol-like substances is associated with reproductive health, metabolism, and developmental issues.
Furthermore, bottled water is not sterile. Once opened, microorganisms quickly multiply. Reusing water bottles can introduce saliva and environmental bacteria into the bottle.
Tap water typically contains beneficial minerals such as fluoride, which can help prevent tooth decay. However, the mineral content in bottled water varies greatly, and research suggests that children who regularly drink bottled water are more prone to tooth decay.
According to Shahzad, excessive consumption of bottled water also poses an environmental burden on the planet. The global consumption of bottled water is enormous, with approximately 1 million bottles sold per minute.
Danish water technology company Aquaporin estimates that the energy required to produce 1 liter of bottled water may be 2,000 times that needed for supplying 1 liter of tap water. The carbon footprint of bottled water is also higher. Taking into account bottling, transportation, and cooling processes, on average, each liter of bottled water generates around 80 grams of carbon dioxide.
The controversy surrounding bottled water is closely linked to the pressure faced by global water resources. Climate change, rapid urbanization, industrial pollution, and population growth are exacerbating water resource stress. UNESCO warns that more than 2 billion people are living in areas where water resources are highly stressed.
Shahzad concludes that bottled water remains crucial in emergencies or situations where water resources are scarce and tap water is genuinely unsafe. However, in most developed countries, bottled water is not necessarily safer or cleaner than tap water.
As the way people access water resources changes due to climate change and pollution, understanding the true differences between bottled water and tap water is more important than ever before.
It is worth noting that PET, used to produce plastic bottles, accounts for 12% of global plastic consumption. Since PET is not easily biodegradable, it is a major source of plastic pollution. After use, it ultimately ends up in landfills or degrades into tiny plastic particles over time, which often enter wastewater and waterways, causing pollution.
Scientists at Northwestern University have developed a simple, non-toxic, fast, and environmentally friendly method to break down the chemical bonds in PET using air and recycle it. This method helps address the issue of plastic pollution.