No matter how enthusiastic you are about living an eco-friendly life, compromises probably happen sometimes. For example, on a hot day, maybe you'll buy bottled water. You know it’s not as responsible as tap water, but it can’t be that much worse. Can it?
Well, according to a recent study, that H2O has a hefty price – and we don’t just mean the dollar markup. Researchers found that store-bought bottled water has an environmental impact that is thousands of times higher than taking it from the tap.
The study found that if all of Barcelona switched to bottled water over tap, the increased production would have 1,400 times more impact on ecosystems and cost 3,500 times more via resource extraction. The researchers also estimate that 1.43 species would be lost annually in this scenario.
“Bottled water consumption has sharply increased in the last years worldwide,” explains paper, published in the journal Science of the Total Environment. “This global trend is partly explained by subjective factors like risk perception and organoleptics [sense perception of the water, e.g. taste and smell], lack of trust in public tap water quality, and marketing by the bottled water industry."
"However, bottled water consumption involves much higher environmental impacts compared to public drinking water supply.”
The study analyzed the relative costs and benefits of three different water choices: bottled, tap, and filtered tap water. Normally, this kind of analysis is split into two separate studies: the environmental impact of a decision, and the health impact. However, this research was different – the team looked at both sides of the equation together, coming up with the best choice for both outcomes.
“We estimated the health and environmental impacts of four drinking water scenarios for the Barcelona population: 1) currently observed drinking water sources; a complete shift to 2) tap water; 3) bottled water; or 4) filtered tap water,” says the paper.
“The scenario where the entire population consumed tap water yielded the lowest environmental impact on ecosystems and resources, while the scenario where the entire population drank bottled water yielded the highest impacts (1400 and 3500 times higher for species lost and resource use, respectively).”
A particular health concern for tap water was the potential for trihalomethane (THM) exposure. These compounds are by-products of the disinfection process of municipal water supplies and are associated with increased bladder cancer risk. However, where public drinking water is safe and high-quality, the authors argue that the risk is far outweighed by the high environmental cost of bottled water.
“Tap water quality has increased substantially in Barcelona since the incorporation of advanced treatments over the last years,” said first author Cristina Villanueva. “While it is true that tap water may contain [THM] derived from the disinfection process […] the risk for health is small, especially when we take into account the overall impacts of bottled water.”
Those impacts, the paper notes, include “non-renewable resource depletion and … the emission of harmful pollutants (e.g. greenhouse gases, particulate matter) into the environment” as well as the well-documented effects on marine life. Micro- and nano plastics have been found almost everywhere – even human placentas – and increased bottled water use only adds to the problem, the team explains.
If you really can’t stand the taste of tap, they note, there’s one solution that’s almost as good: filtering your water.
“Considering both the environmental and the health effects, tap water is a better option than bottled water, because bottled water generates a wider range of impacts,” study co-author Cathryn Tonne explained.
“Filtered tap water is a good alternative. Even though we didn't have enough data to measure its environmental impact fully, we know it is much lower than that of bottled water.”