That 130 litres of water goes into making your average coffee is a statistic that amazes most people. Even more surprising is that hardly anyone, even in the business community, has the foggiest idea how much water goes into manufacturing our favourite consumer products, from field to factory.
Seeking to address the dearth of information on the water required to produce a single product, from ready meals and soft drinks to t-shirts and electronic items, a variety of organisations have over the years floated the idea of water footprint labelling.
The general premise is that quantifying water inputs, like nutritional and calorie labels on food items, will help to influence purchasing habits, encouraging consumers to resist highly water intensive products. It would incentivise product manufacturers to scale back unnecessary waste and awaken consumer consciousness about water insecurity.
According to Dr Zafar Adeel, chair of UN-Water, the United Nations thinktank, not only does water footprint labelling make sense, but it is just around the corner. "People are often surprised and then ask, 'why didn't we know about this before?'
"I wouldn't call it a pipe dream," he says. "It will take five to 10 years for it to become fairly common."
Adeel suggests that a few pioneering companies may take the lead, rather than the government intervening. This in turn would spur industry-wide initiatives.
Growing consumer demand will be an important driver, he explains. "As we come up with new ways of measuring sustainability and the green economy, that will create back pressure on the private sector to come up with these schemes to provide more information."
Not everyone shares Adeel's optimism, however. Many critics regard any water footprint labelling scheme as a well-intentioned but ultimately meritless initiative, which risks further bamboozling already confused consumers.
Alistair Knox, chairman of the Association of Suppliers to the British Clothing Industry, is one influential voice in the clothing industry to pour cold water on the idea. The proposal is just not on the clothing industry's agenda, he says, and is far below issues such as the durability of garments or energy usage.
"It would be a bit pointless. There is already a huge amount of information on garment labels that people very rarely, if ever, look at," he says, adding that the industry would regard any serious proposal as a "little bit bizarre".
In Knox's view, any figure assigned to a clothing product for water usage is "dubious" as it is "from difficult to impossible" to calculate accurately beyond a generic average. He uses the example of a cotton yarn, the fibres of which may have come from several regions, each of which may have had different irrigation systems.
"How are you going to average that? Whatever number you come up with is just somebody's thumb in the air." The same could be said for many other consumer industries, such as electronic goods.
Knox also challenges the idea that water volume use is an important consideration for consumers. "The bottom line is that water recycles … Where is that water now? It's back in the system."
The sense that water volume labelling is too simplistic is shared by Felix Ockborn, environmental sustainability coordinator for water at high-street clothing retailer H&M. While Ockborn welcomes product scoring on sustainability performance, he says it is just as vital to consider the context of the water consumption in any labelling system.
"Only providing a volumetric product footprint would be misguiding if it does not incorporate where the water was taken from," he says. "What is most important is what we and other companies do to ensure that water is used responsibly."
Simon Davidoff, senior director of strategy for industrial services at Siemens, supports the idea of water footprint labels alongside energy use indicators. Technological advances mean it is relatively easy to quantify consumption and wastage in factory environments, he says.
Like Adeel, Davidoff believes water footprint labels are now inevitable. "Consumers will demand it," he says. The challenge will be in agreeing how far back companies should go to measure water inputs. More