The consumption of bottled water has been rising sharply in recent years on a global scale, due in part to subjective perceptions of taste or odour, lack of trust in the quality of public tap water, and the marketing of bottled water companies. Cristina Villanueva and her team set out to provide objective data on two different water consumption options: bottled water and tap water (filtered or not). The novelty of their analysis was that it took into account not only the human health impact of these choices, but also their environmental impact (i.e. a life cycle assessment). For the latter, the researchers used special software that makes it possible to estimate the damage to ecosystems and resource availability, as well as indirect impacts on human health derived from the production process. For the health impact assessment, they used data on water consumption patterns and levels of chemical compounds in the water supply from Barcelona’s Public Health Agency.

Bottle trouble

The results show that, if the entire population of Barcelona were to choose bottled water, the environmental impact would be equivalent to losing 1.4 species per year, and the cost of resource extraction would be 84 million USD per year. This impact would be 1,400 and 3,500 times smaller, respectively, if the whole population were to drink tap water. The health impact assessment shows that, due to the high quality of the tap water in Barcelona, the risk to health due to chemicals linked to the water disinfection process is very low (estimated at 2 hours of lost life expectancy); domestic filtration lowers this risk even further. “The risk is very small if we consider the overall impacts of bottled water,” says Villanueva.

“Our analysis clearly shows that choosing to drink tap water is best for our health and that of the planet,” concludes Cathryn Tonne.