It measures the amount of water that goes into every aspect of production, including growing, manufacture and distribution. It can be measured for a single process, such as growing rice, or for more complex products like a new car. We can also track the water footprints of companies and even entire countries.
The water footprint covers three categories of water usage; Green – the rainwater used in a product, Blue – the surface or ground water used in a product and Grey – the water used to dilute pollutants to a safe level. All these combine to give an overall amount in litres.
There are many products that use a surprisingly large amount of water in their production. Cotton is unfortunately a good example of a product with a massive water footprint, often due to inefficient water usage. In India, the world’s second largest producer of cotton, a lack of water efficiency means that 22,500 litres of water are used to produce just 1 kilogram of cotton – that’s 22,500,000 litres per ton. This inefficient use of water creates a huge footprint of around 38 billion cubic metres of water a year, which could supply 85% of India’s population with 100 litres per day for a year. In contrast, China, recognised as both the biggest and most water efficient grower in terms of large-scale production, uses around 5,404,000 litres per ton of cotton.
All that cotton goes into many of the clothes we wear every day. On average, it takes around 10,000 litres of water to create a single pair of blue jeans. In response to the increased awareness of unsustainable water footprints, some manufacturers are taking steps towards conserving water and slashing their products’ water footprint. By changing the finishing process of jeans, which often involves multiple washes, jeans manufacturers can cut 28% off water usage in their production. Jeans made from recycled denim can also reduce the amount of water used in production by 96%. Companies are also experimenting with jackets and shirts made of recycled plastic bottles, which has the bonus of reducing the amount of plastic in our environment.
The use of water is not just disproportionate in the clothing and cotton industry, it’s also clear in food manufacturing. Virtually anything that requires farming consumes huge amounts of water due to the additional irrigation often necessary to grow the crops, especially in areas where supplies of rainwater are insufficient. Typically, one cup of coffee requires 140 litres of water in the growing and production of the coffee. For every kilo of beef, around 16,000 litres of water are used, mostly to sustain the cows that produce the meat. Savings can be made through choosing organic produce that requires less irrigation, as well as by selecting local products which reduces the water footprint due to reduced transportation requirements. Science and technology can also play a role, with recent work in GMO crops allowing some yields to remain the same but using 25% less water. This is done by mutating a specific protein found in all plants, reducing the amount of water the plant passively loses while intaking carbon dioxide.
Business are already acknowledging the importance of water footprints, and some have started taking serious measures to reduce them. Some beverage companies are attempting to give back the water they use by increasing water efficiency in local communities. Some have already achieved their goal of offsetting water use by over 100% percent. Software companies are creating buildings and offices focused around sustainability and rainwater usage in an attempt to create water net zero buildings.
Using water efficiently means creating products in ways different to the traditionally water intensive route. This can be achieved in many ways, such as recycling used water, harvesting rainwater and carrying out a companywide water audit to find efficiencies. These are a few of many strategies that can be used to help cut down water footprints and contribute to the preservation of our valuable water resources.