Freshwater is a scarce resource; its annual availability is limited and demand is growing. The water footprint of humanity has exceeded sustainable levels at several places and is unequally distributed among people. Good information about water footprints of communities and businesses will help to understand how we can achieve a more sustainable and equitable use of fresh water.

There are many spots in the world where serious water depletion or pollution takes place: rivers running dry, dropping lake and groundwater levels and endangered species because of contaminated water. The water footprint helps to show the link that exists between our daily consumption of goods and the problems of water depletion and pollution that exist elsewhere, in the regions where our goods are produced. Nearly every product has a smaller or larger water footprint, which is of interest for both consumers that buy those products and businesses that produce, process, trade or sell those products in some stage of their supply chain.

First of all, environmental awareness and strategy is often part of what a business regards as its ‘corporate social responsibility’. Reducing the water footprint can be part of the environmental strategy of a business, just like reducing the carbon footprint. Second, many businesses actually face serious risks related to freshwater shortage in their operations or supply chain. What is a brewery without secure water supply or how can a company in jeans survive without continued supply of water to the cotton fields? A third reason to do water footprint accounting and formulate measures to reduce the corporate water footprint is to anticipate regulatory control by governments. In the current stage it is not so clear how governments will respond, but obviously regulations in some sectors of business may be expected. Finally, some businesses see a corporate water footprint strategy also as an instrument to reinforce the corporate image or to strengthen the brand name.

Consumers can reduce their direct water footprint (home water use) by installing water saving toilets, applying a water-saving showerhead, closing the tap during teeth brushing, using less water in the garden and by not disposing medicines, paints or other pollutants through the sink.

The indirect water footprint of a consumer is generally much larger than the direct one. A consumer has basically two options to reduce his/her indirect water footprint. One option is to substitute a consumer product that has a large water footprint by a different type of product that has a smaller water footprint. Examples: eat less meat or become vegetarian, drink tea instead of coffee, or even better drink plain water. Not wearing cotton but artificial fibre clothes saves a lot of water. But this approach has limitations, because many people don't easily shift from meat to vegetarian and people like their coffee and cotton. A second option is to stick to the same consumption pattern but to select the cotton, beef or coffee that has a relatively low water footprint or that has its footprint in an area that doesn’t have high water scarcity. This requires, however, that consumers have proper information to make that choice. Since this information is generally not available in the world of today, an important thing consumers can do now is ask product transparency from businesses and regulation from governments. When information is available on the impacts of a certain article on the water system, consumers can make conscious choices about what they buy.

Businesses can reduce their operational water footprint by saving water in their own operations and bringing water pollution to zero. Keywords are: reduce, recycle and treat before disposal. For most businesses, however, the supply-chain water footprint is much larger than the operation footprint. It is therefore crucial that businesses address that as well. Achieving improvements in the supply chain may be more difficult – because not under direct control – but they may be more effective. Businesses can reduce their supply-chain water footprint by making supply agreements with certain standards with their suppliers or by simply changing to another supplier. In many cases it probably means quite something, because the whole business model may need to be transformed in order to incorporate or better control supply chains and to make supply chains fully transparent to consumers. Among the various alternative or supplementary tools that can help improving transparency are: setting quantitative water-footprint reduction targets, benchmarking, product labelling, certification and water footprint reporting.

Traditionally countries formulate national water plans by looking how to satisfy water users. Even though countries nowadays consider options to reduce water demand in addition to options to increase supply, they generally do not include the global dimension of water management. In this way they do not explicitly consider options to save water through import of water-intensive products. In addition, by looking only at water use in the own country, most governments have a blind spot to the issue of sustainability of national consumption. As a matter of fact many countries have significantly externalized their water footprint without looking whether the imported products are related to water depletion or pollution in the producing countries. Governments can and should engage with consumers and businesses to work towards sustainable consumer products. National water footprint accounting should be a standard component in national water statistics and provide a basis to formulate a national water plan and river basin plans that are coherent with national trade policy and national environmental policy.

As a consumer, your water footprint is sustainable when (a) the total remains below your equal share of the available freshwater resources in the world, and (b) no component of the total water footprint presses at places where or times when local environmental flow requirements are violated.

This is a question that we receive from people that are familiar with the idea of carbon offsetting. In the case of carbon it doesn’t matter where mitigating measures are taken, so one can offset own CO2 emissions by helping to reduce CO2 emissions or enhancing carbon sequestration elsewhere. In the case of water, this is different, because water depletion or pollution in one place cannot be compensated by whatever measure in another place. The focus should therefore be on reduction of the own water footprint, at the places where and times when this water footprint causes problems. We should do all that is ‘reasonably possible’ to reduce the own water footprint, both the direct and indirect one. This holds for both consumers and businesses. Only in second instance, when everything has been done to reduce the own water footprint, one can consider offsetting. This means that the residual water footprint is offset by making a ‘reasonable investment’ in establishing or supporting projects that aim at a sustainable, equitable and efficient use of water in the catchment where the residual water footprint is located. The terms ‘reasonably possible’ and ‘reasonable investment’ include normative elements that need further quantitative specification and about which we need to reach societal consensus.

Generally the price paid for water is far below its real economic cost. Most governments subsidise water supply on a huge scale by investing in infrastructure like dams, canals, distribution systems, and wastewater treatment. These costs are often not charged to the water users. As a result, there is insufficient economic incentive for water users to save water. Besides, due to the public character of water, water scarcity is generally not translated into an additional component in the price of goods and services that are produced with the water, as happens naturally in the case of private goods. Finally, water users generally do not pay for the negative impacts that they cause on downstream people or ecosystems.

No, some components of the water footprint can have negative environmental impacts, but other components may be without any problem. Besides, it deserves consideration whether one has a total water footprint below or beyond one’s equal share of the available freshwater resources in the world.

The water footprint shows the plain volumes of water consumption and pollution, including where and when, in all phases of the supply-chain of a product. This is interesting from two perspectives. First, the water footprint tells the total water volume apparently appropriated for a certain product. Since freshwater availability on earth is limited it is important to know how it is allocated over various purposes, to feed debates such as water for nature versus food, water for food versus energy, or water for basic needs versus luxury goods. Besides, it is interesting to see how water is shared among people. Second, the water footprint forms the basis for a detailed impact assessment. The water footprint map (showing where and when what volumes of water are being appropriated) is the basis for assessing the local impacts of the various water footprint components. For this purpose the water footprint map can be overlaid with a map showing local water stress. In this way one can identify the hotspots where water footprint reduction is most urgent.

There is no general answer to this question, because it depends on the product, available technology, local context, etc. Besides, one has to keep in mind that the question includes a normative element, which implies that it needs to be answered in a societal-political context. A few general things can be said, however. First of all, one has to distinguish between reduction targets with respect to the green, blue and grey water footprint. As for the grey water footprint, which refers to water pollution, one can demand a reduction to zero for all products, at least in the long term. Pollution is not necessary. A zero grey water footprint can be achieved by prevention, recycling and treatment. Only thermal pollution (by water use for cooling) is difficult to reduce to zero. The blue water footprint in the agricultural stage of products can often be brought down by a factor two by reduction of consumptive water losses; in the industrial stage it will depend very much on the sector and what has already been done. Technologically, industries can fully recycle water, so that the blue water footprint can everywhere be reduced to the amount of water that is actually being incorporated into the product. Benchmarks can be developed for specific products by taking the performance of the best producers as a reference. Another general rule for any water footprint mitigation strategy is to avoid the water footprint pressing in areas or times where environmental flow requirements are violated. A final rationale for a water footprint mitigation strategy can be the fair sharing of water resources. This may be the basis for water footprint reduction particularly for large water users.

The two concepts nicely complement each other, each concept addressing another environmental issue: the carbon footprint addresses the issue of climate change, the water footprint relates to the issue of freshwater scarcity. In both cases, a supply-chain perspective is promoted. There are also differences, however. For a carbon emission it doesn't matter where it happens, but for a water footprint is does matter. A carbon emission in one place can be offset by carbon emission reduction or sequestration in another place, which is not true for water: one cannot reduce the local impact of water use in one place by saving water in another place.

Desalination of salt or brackish water can only be a solution for freshwater scarcity in a limited number of applications, not because one cannot obtain the right quality of water for all purposes, but because desalination requires energy, another scarce resource. In fact, desalination is a way of substituting one scarce resource (freshwater) by another one (energy). If at a certain spot the freshwater issue is pressing even more than the energy issue, one can decide in favour of desalination, but in general it doesn’t make sense to propose desalination as a general solution to freshwater scarcity. Besides, apart from the energy argument, desalination is still expensive, too expensive for use in agriculture where most of the water is used. Finally, salt or brackish water are only available along coasts, which means that bringing desalinated water elsewhere would imply additional costs (again including energy).

In a world where many products are related to water depletion and pollution it is very useful to make the history of products more transparent. It is good to have the facts publicly available, so the consumer has a choice. Information can be provided on a label or can be made available through internet. This is most useful for products that often have large effects on water, like products that contain cotton or sugar. For consumers it would be helpful to integrate a water label in broader labels that include other issues as well, like energy and fair trade. Ideal would be a world in which we don’t need labels because we can trust that all products meet strict criteria.