Hidden water is an important part of water use. It may not be visible, but millions of gallons of virtual water go into making the consumer goods Americans buy, use and throw away. Manufacturing everyday materials like paper, plastic, metal and fabric takes water – a lot of it. Knowing how much water it takes to make the raw materials and products we all use and consume is an important first step towards water conservation and using water more productively.
Hidden Water: How the Water Footprints of Consumer Goods are Calculated
Hidden water is water that is not felt or seen and it is required for almost every step in the production processes for many raw materials and finished products. The water footprint of a product is calculated by adding up all of the water required for each step of the production process. Table 1 lists a sampling of water footprints for the manufacturing of some common consumer goods.
Table 1. Water Footprint of Common Consumer Items.
|Car||13,737–21,926 gallons (52,000–83,000 liters)|
|Leather Shoes||2,113 gallons (8,000 liters)|
|Smartphone (mobile)||3,190 gallons (12,760 liters)|
|Jeans (cotton)||2,866 gallons (10,850 liters)|
|Bed Sheet (cotton)||2,576 gallons (9,750 liters)|
|T-shirt (cotton)||659 gallons (2,720 liters)|
|Paper (1 piece; A4)||1.3 gallons (5.1 liters)|
The Water Footprint Network (whose research provides some of the data used in the WFC) defines these components as:
Blue Water Footprint: The amount of surface water and groundwater required (evaporated or used directly) to produce an item.
Green Water Footprint: The amount of rainwater required (evaporated or used directly) to make an item.
Grey Water Footprint: The amount of freshwater required to dilute the wastewater generated in manufacturing, in order to maintain water quality, as determined by state and local standards.
How Much Virtual Water is in a Smartphone?
Take smartphones, for example. Their water footprint comes from the virtual water associated with their manufacturing – what’s known as the “grey water footprint.”
Phones are composed of many pieces created in multiple steps, and each step consumes water. Numerous resources, materials and parts go into smartphone manufacturing, including rare earth metals (e.g., lithium), tin, glass and plastics. The supply chains for these materials stretch around the world to places like Indonesia, the Philippines and China. Production might include steps like mining for precious metals, creating synthetic chemicals for glue and plastic and assembling and packaging. Collectively, the water associated with each step adds up to the blue water footprint.
In addition, manufacturing the parts creates wastewater that is released into surrounding waterways. Those waterways often have pollution limits that manufacturers must meet before they can send their wastewater down the pipe and into the waterway. The water used to clean and dilute the wastewater adds up to the grey water footprint, and in the case of the smartphone, makes up the largest portion of its total water footprint.
When the water required for all the steps to make a smart phone is added up, the water footprint of the production of a single phone is an estimated 3,190 gallons.
The Water Footprint of Everyday Paper, Plastic and Cotton
Similarly, water is consumed in manufacturing most other products. For example, it takes 22 gallons of water to make one pound of plastic. In fact, it takes at least twice as much water to produce a plastic water bottle as the amount of water contained in the bottle. The water footprint of one pound of cotton is 1,320 gallons. That equals over 650 gallons of water for one new cotton t-shirt. Even refining gasoline takes water – approximately one to 2.5 gallons of water to refine one gallon of gasoline.
To meet all of these needs, industrial facilities in the US withdraw over 15.9 billion gallons of water per day. Fortunately, due to increasingly efficient manufacturing practices, most factories have reduced water use by 12 percent since 2005, and 33 percent since 1970.
All told, the water that keeps America afloat on a sea of consumer goods is enormous. As some of the biggest shoppers on the planet, the average American’s water footprint for buying, using and throwing away consumer goods (excluding food) is 583 gallons of water per day.
Save Water With the Three Rs: Reduce, Reuse, Recycle
The adage “reduce, reuse, recycle” becomes even more relevant given all the water and other resources that go into making all the products consumed in America. Many consumer goods are made to be thrown away, so they pile up in landfills, wash into the ocean or litter the landscape.
Buying fewer products in the first place reduces the overall number of products that are made, and, in turn, reduces the amount of water needed by the factories that make these products. Additionally, recycling consumer goods can have a positive effect. In 2012, for example, the US threw out over 24 million tons of paper and almost 29 million tons of plastic – both of which are water-intensive materials that can be re-used and/or recycled. Recycling a pound of paper – the same amount found in a typical daily newspaper – saves 3.5 gallons of water.
Small actions like recycling at home, reusing items when possible and using fewer plastic bags and paper towels can make a small but cumulative difference in water consumption. Reducing the need for new products in the first place – ending overconsumption – is the strategy that saves the most water. Avoiding purchases of disposable, low-quality goods that are made to go in the trash makes a big difference. Buying used items and thrifting – especially for clothing – or buying products that are of higher quality, reusable and, if need be, recyclable, are the best options when new purchases are necessary.
The Hidden Water in Energy
The average American today uses about five times more electricity than they did 50 years ago. This increase is significant because it takes a substantial amount of water to create energy. Water is used to cool steam electric power plants – fueled by coal, oil, natural gas and nuclear power – and is required to generate hydropower. Water is also used in great quantities during fuel extraction, refining and production. So, wasted energy is, in effect, wasted water.
Nobody will have a water footprint of zero because it takes water to make just about everything we choose to buy, eat, use and throw away. Individual daily decisions might seem small, but cumulatively they can have a great impact.