According to a recent research project, water sold in plastic bottles could be thousands of times worse for us, and the environment, than water from your humble tap. By Jeremy Torr.

Barcelona, Spain. November 2021. Most people buy and drink bottled water because they think it is better for them. Tap water is purified in industrial plants (but so is much bottled water), and can have more sterilising additives in it than bottled water. But the overall impact on the planet of bottled water in one European city has been calculated as being thousands of times worse than the effect of drinking water from a tap.

The key environmental and safety issue, says Ertug Ercin of the Netherlands-based Water Footprint Network (WFN), is not just the additives that might be in the water, but the entire water footprint of the final, drinkable product. The real water footprint includes all freshwater used in production, including the processing, packaging and production, as well as the perceived quality of the water.

"Packaging alone makes a significant (environmental) footprint," says Ercin, noting that up to three litres of water might be used in the processes required just to make a single 500ml plastic bottle. “That means the amount of water going into making the (plastic) bottle could be up to six or seven times what's (drinkable) inside the bottle.”

Then there’s the paper label on the bottle – that needs litres of water to produce too. And fossil fuel emissions due to transporting bottled water in bulk. Even the raw material for the plastic, oil, needs what Ercin calls “substantial amounts” of resource extraction. “Bottled water companies (along with many other beverage companies) should include the water (consumption) in their supply chain analysis,” he asserts.

And according to new research from the Institute for Global Health (ISG) the perception that tap water is less healthy than bottled water is also something of an urban myth. The ISG focused its research on the city of Barcelona, which reports that over 50% of its 1.35 million inhabitants drink bottled water at some time.

“Tap water quality (in Barcelona) has increased substantially since (the introduction of) advanced treatments,” says Cristina Villanueva, lead researcher at ISG. “However, this … improvement has not been mirrored by an increase in tap water consumption, which suggests that water consumption could be motivated by subjective factors other than quality.” ISG cites things like risk perception, taste, odour, lack of trust in public tap water quality and marketing by bottled water companies as all influencing drinkers looking at their water choice.

The researchers used data from the Barcelona Public Health Agency to establish water consumption patterns, along with levels of chemical compounds found in water supply. Then, a Life Cycle Assessment (LCA) was used by researchers to estimate the damage to ecosystems and ongoing resource availability as well as indirect impacts on human health derived from the sourcing and supply of both bottled and tap water.

“One of the subjective factors is the perceived presence of chemical compounds in tap water. While it is true that tap water may contain trihalomethanes (THM) from the disinfection process … our study shows that due to the high quality of the tap water (here) the risk for health is small.”

But the risk to the planet from bottled water is anything but small, reports the study. It estimates that if all the current inhabitants of Barcelona abandoned tap water and switched to bottled, almost 1.5 animal species would become extinct due to environmental imp[act. The extraction of raw materials alone would cost US$83.9 million a year. And the impact on ecosystems would be ‘approximately1,400 times more than if the whole population moved to drinking tap water, says the report.

But most horrifyingly, bottled water would be up to 3,500 times more impactful than tap water in terms of overall natural resource extraction and depletion. “Our results show that considering both the environmental and the health effects, tap water is a better option than bottled water, because bottled water generates a much wider range of impacts,” says ISG researcher Cathryn Tonne.

“The use of domestic filters, in addition to improving the taste and odour of tap water, can reduce substantially THMs levels too. For this reason, filtered tap water is a better (environmental) alternative.”

Despite this, it seems the companies marketing bottled water accentuate personal risk and preference over ongoing environmental issues. “Few companies take the whole water-use picture into account when calculating their water use,” notes the WFN’s Ercin. He sayts that should change.

“Just as companies are beginning to calculate their carbon footprint, they also need to analyse their water footprints to find opportunities for conservation.” Where’s my refillable bottle?

Want to know what your water footprint is? Go to https://waterfootprint.org/media/downloads/AquaPASS_WFN_Final.pdf and download a chart to see how you can help minimise water waste.