The water footprint of a product is the amount of water that is consumed and polluted in all processing stages of its production. A product water footprint tells us how much pressure that product has put on freshwater resources. It can be measured in cubic metres of water per tonne of production, or litres per kilogram, gallons per pound or per bottle of milk.
By measuring the volume and source of water consumed in the production of a product and the volume of water needed to assimilate pollutants so that water quality standards are met, we can get a picture of how a specific product contributes to the growing concerns of water scarcity and degraded water quality. It also allows us to compare different products for their relative contribution to these critical water issues.
The water footprint of a final product, e.g., a pair of jeans, is the summation of the water footprint of each step, or process, required to produce that product. A pair of jeans will require cotton to be grown, ginning and spinning of the fibres, weaving, sewing and wet processing of the fabric to ultimately have the finished product. Each step has a direct water footprint and an indirect water footprint. The direct water footprint of one process becomes the indirect water footprint of the next process. In this way, the full amount of water consumed or polluted is taken into account in the product water footprint.
By measuring the water footprint of a product in volumes of water per unit of production, it is possible to assess how efficiently the product has been produced. Or, another way of saying this is the product water footprint tells us how productively freshwater resources are being used – that is, how many units of production have resulted from each litre of water used. This measure of resource efficiency can be applied to both the amount of water consumed, the green and blue water footprint, and the amount of assimilation capacity used, the grey water footprint. If we produce a product with a smaller grey water footprint, we have put less pressure on the freshwater resource and contributed less to water quality degradation.
As many as three billion people are already living in areas with water scarcity and river basins worldwide have declining water quality; if we are going to feed, clothe and house all the people on the planet we need to be more efficient with our water resources. The product water footprint can help us identify where there are opportunities for water footprint reduction and improvements in resource efficiency.
Water footprint benchmarks can be set by looking at the water footprint resulting from the use of best practices or best available technologies or by selecting the water footprint achieved by best performers in a particular sector. Water footprint benchmarks can be used to set targets for water footprint reductions in an individual process, e.g., the hot-rolling of steel, for a product, a sector or a company.
Water footprint benchmarks can provide useful information to governments and can help us achieve sustainable development goals. By focusing investments, whether in training, infrastructure or better management practices, on the poor performers, the overall water footprint of production can be reduced, thereby alleviating the pressure we put on freshwater resources and making the water we do use more productive.
A water footprint can also be used to measure the role of a product in the economy. By relating the green, blue and grey water footprint to economic measures such as profits per unit of product, jobs or the proportion of the GDP created, the water footprint can show us the full range of economic benefits coming from the products produced in an area. This information can contribute valuable insights on how we can meet different societal goals through allocation of water resources across different water uses and users.
The water footprint doesn’t just tell us how much water is used to produce a product; the water footprint occurs at a specific place during a specific time. This is important because there are variations in the amount of water and assimilation capacity available in different places and during different times of the year. A water footprint, which occurs in a water rich location or during the wet season still puts the same pressure (volumes consumed) on water resources but that pressure may not be putting the overall water use in a river basin or from an aquifer beyond the maximum sustainability threshold.
Legend: The green, blue, grey and total water footprints within Latin America & Caribbean (1996-2005). The data are shown in mm/y on a 5 by 5 arc minute grid. Source.
To understand the sustainability of a product’s water footprint, we need to look at the cumulative water footprint in comparison to the local water resources. In this case, we use the volume of water consumed or assimilation capacity used during a month, or a season, or year. Combined together, the water footprint of all production in a particular location or time period tells us whether we’ve crossed the sustainability threshold and our product is unsustainable.
Legend: Annual average monthly blue water scarcity in Latin America and the Caribbean estimated at a resolution level of 30×30 arc minute grid cells. Low blue water scarcity corresponds to green colours (<1.0), moderate to yellow (1.0-1.5), significant to orange (1.5-2.0) and severe to red (>2.0). Source.
Knowing the water footprint of the products and goods we produce and consume, allows:
Check out our national explorer to see which countries have a higher water footprint and to compare countries.
Find out how you can improve the water footprint of the products you produce in our business section.
Find out how you country can better manage its national water footprint in our national section.
Find out how you can improve your own water footprint in our personal section.