Water Footprinting (as managed by the Water Footprint Network)




Water footprinting—a methodology introduced in 2002 and developed primarily by researchers at the University of Twente (Netherlands)—measures the total annual volume of freshwater used to produce the goods and services consumed by any welldefined group of consumers, including a family, village, city, province, state, nation, and more recently, a business or its products. Water footprints (WFs) are intended to allow these entities to better understand their relationship with watersheds, make informed management decisions, and spread awareness of water challenges worldwide. Throughout this decade, the water footprinting method has been refined, beginning to incorporate ways to achieve more reliable and spatially and temporally explicit data and to better account for water quality and impacts, among other things.

Water footprinting was originally developed as an accounting tool for water resources management (WRM) and is currently well-established as a leading methodology in this field. WRM accounting to this day remains one of the primary roles of water footprinting, with the WF measure allowing policymakers, planners, and managers to map various water uses in a system (e.g. agricultural, municipal, industrial), as well as the amount of water used by the community, country, region, etc. to produce the goods and services they consume. For WRM, the actual volume of water used is critical information as it allows decision-makers to, for instance, understand how water use relates to overall supply volumes; how water is allocated among users within their system (and if it is allocated equitably); which needs (e.g. environmental, basic human) are being met; and which water uses are providing the most economic value per unit volume. Armed with WFs, policymakers and water managersare better positioned to make water allocation and other decisions.

Water footprinting in the context of WRM was born out of and is underpinned by the concept of virtual water—the volume of water used to produce individual goods and services (most notably crops) throughout all stages of production. One critical aspect of virtual water is that it accounts for the water needed to make the goods and services that are imported into a system. Thus WFs in the WRM context account for virtual water trade through the notion of internal and external WFs, which track how much of a region’s water resources are used for goods and services consumed in that area versus how much foreign water is used for those same purposes. The volume-focused virtual water concept (measured by means of the WF) has proven quite helpful for water managers and policymakers as they consider the merits of domestic food and/or industrial production versus importing (and/or not exporting) waterintensive goods, in conjunction with shifting water allocations to uses with more economic value in water-stressed areas.

Only in the last couple of years has the private sector begun to use WF to assess their direct and indirect water use, bringing with them the new questions and needs of the accounting method. A key distinction is that water footprinting for WRM focuses on providing information that helps water managers understand all volumetric needs (i.e., communities, ecosystems, businesses) and prioritize those needs in the face of scarcity based on societal, environmental, and economic values. In contrast, companies are typically concerned with the ability of available water supplies to meet their own needs and understanding their risks and impacts associated with the WF across multiple different watersheds. This is because of their desire to understand their indirect water use (i.e., the water embedded in their supply chains) and because of the global reach of most corporations’ value chains.


Scope, structure, and outputs

Water footprinting focuses solely on providing a method for companies to measure their water use and discharge; within the context of the Water Footprint Network, the WF itself does not aim to assess the status of watersheds or water-related impacts per se. A WF captures the volume, location, and timing of water uses and discharges. WFs are divided into three separate components—the blue, green, and gray—all of which are expressed in terms of water volume. These components are meant to be considered both separately and together as a total WF (i.e., the sum of the blue, green, and gray water footprints). The three WF components are defined as follows:

  • Blue water – the volume of consumptive water use taken from surface waters and aquifers.
  • Green water – the volume of evaporative flows (found in soils rather than major bodies of water) used.
  • Gray water – the theoretical volume of water needed to dilute pollutants discharged to water bodies to the extent that they do not exceed minimum regulatory standards.

The green and blue components of a WF focus on consumptive water use (i.e., the volume of water removed from local water system by evaporation, inclusion in a product, water transfer, or otherwise). They do not include those uses of water that are eventually returned to the same system from which they are withdrawn (i.e., non-consumptive uses). To the degree to which non-consumptive water use is addressed, it is done within the gray water component.

A WF as described above is only one component of a larger water footprint assessment. A WF is purely a volumetric account of water appropriation. A broader WF assessment looks at the sustainability of that appropriation and steps that can be taken to make it more sustainable. A full water footprint assessment is divided into four stages:

  • Setting goals and scope
  • WF accounting (the traditional “water footprint”)
  • WF sustainability assessment
  • WF response formulation

The first phase sets the boundaries of the assessment. The second phase is the traditional water footprint where water uses are measured by volume. The third phase is essentially an impact assessment where water use is compared with local water availability data. In the final stage, response options such as strategies, targets, or policies are formulated. The “water footprint” and “water footprint assessment” terminology is the source of some confusion. For the purpose of this report, “water footprint” refers solely to the second phase presented here. Current practice in corporate water accounting has in most cases consisted of only the first two stages. “Sustainability assessments” are important, but are not yet common practice.

Corporate WFs measure the total volume of water used directly and indirectly to run and support a business. They are typically scoped to focus at the company-wide or facility level but can also focus on specific products and their water use throughout a company’s value chain (e.g. raw material production, manufacturing, distribution). Corporate WFs are meant to be divided between their operational and supply chain components; however, comprehensive assessments of water use in a company’s supply chain through water footprinting are not widely practiced to date due to the difficulty in obtaining data for large supplier networks.

SAB Miller’s Water Footprint in the Czech Republic

Source: Water Footprinting: Identifying & Addressing Water Risks in the Value Chain. SABMiller and
WWF-UK. August 2009.


Financial and personnel requirements

The time and financial requirements for water footprint assessments vary depending on whether companies’ water use is measured using company data or databases (e.g. FAOSTAT or CROPWAT) for their inputs and whether the assessment is company-wide or for a specific product. If the necessary data are readily available, one qualified person can complete a product water footprint in a matter of weeks. It may take roughly five months for a product assessment and over a year for a company-wide assessment if a company must collect its production data. This process becomes progressively shorter as the amount of pre-existing database input used increases. It can take only one-to-two weeks when databases comprise a large portion of input data (Zarate, 2010) (Grant, 2010).

A full product-level WF assessment could cost roughly around 40,000-50,000USD. A company-wide assessment may cost anywhere from 50,000-200,000USD. The WFN Secretariat provides technical support at a rate of roughly 20,000USD for a product assessment and perhaps twice that for a company-wide assessment. Corporate personnel typically spend five person days per month to collect and analyze data, typically at a cost of 1,000USD/person day. The amount of time required of operations managers varies depending on the availability of data (Zarate, 2010) (Grant, 2010).

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