Water Footprint

The water footprint is an indicator used in environmental sustainability and natural resource management. It refers to the total volume of freshwater used, both directly and indirectly, to produce the goods and services consumed by an individual, community or business. As water scarcity and climate change become pressing global concerns, measuring and managing the water footprint has become a priority for governments, companies and citizens.

What is the water footprint?

The concept of the water footprint was introduced by Professor Arjen Hoekstra in 2002 and is defined as the total amount of freshwater used, directly and indirectly, to produce goods and services. It captures not only the water consumed on site but also the water used throughout the supply chain.

The water footprint has three components:

• Blue water footprint: freshwater abstracted from surface or groundwater sources (rivers, lakes and aquifers) that is not returned to the same catchment in the same period.
• Green water footprint: rainwater stored in the soil and taken up by plants during growth, particularly relevant in agriculture.
• Grey water footprint: the volume of freshwater required to assimilate pollutants so that water quality stays within agreed standards.

This approach gives a clearer view of water use across different production stages than a single abstraction figure.

Why measuring the water footprint matters

Measuring the water footprint helps identify opportunities to save water, reduce environmental impact and improve water management. According to the FAO and the UN World Water Development Report, agriculture accounts for around 70% of global freshwater withdrawals, which underlines the need to use water efficiently in farming and in sectors such as industry and energy.

Measuring the water footprint is also useful for:

• Identifying risks: companies can assess their exposure to water scarcity and take action to mitigate it, often as part of a wider water risk assessment.
• Ensuring transparency: consumers and stakeholders increasingly expect accurate information on the environmental impact of products and services.
• Supporting reporting: water use is a material topic under frameworks such as ESRS E3 on water and marine resources.

How is the water footprint calculated?

Calculating the water footprint involves collecting data on water use at each stage of the supply and production chain. It can be complex because it requires integrating data from multiple sources and distinguishing the different types of water use.

Standardised methodologies, such as those of the Water Footprint Network and the ISO 14046 water footprint standard, allow organizations to calculate their water footprint consistently. These methods consider the blue, green and grey components and draw on life cycle assessment (LCA) to evaluate impact.

A practical example

To illustrate, consider the production of one litre of milk. It includes:

• the water used to grow feed and sustain the cows (mostly green water footprint);
• the water abstracted for cleaning facilities and processing the milk (blue water footprint);
• the water needed to dilute the pollutants generated during production (grey water footprint).

Adding these components gives the total water footprint of the product, which varies with geographical location and agricultural practices.

How is the water footprint related to the carbon footprint?

The water footprint and the carbon footprint are closely linked, because many activities that generate greenhouse gas emissions also consume large amounts of water. Generating electricity from fossil fuels, for example, requires significant water for cooling, contributing to both footprints. For this reason, an integrated approach to measuring and managing both indicators helps organizations find synergies and design more effective strategies to reduce their overall environmental impact.

Benefits of reducing the water footprint

Reducing the water footprint benefits the environment and can bring economic and reputational advantages:

• Cost savings: optimising water use can reduce operating expenses, especially in water-intensive sectors.
• Stronger reputation: companies that adopt sustainable practices are viewed more favourably by consumers and investors.
• Access to finance: many financial institutions offer better conditions to businesses with credible sustainability commitments.

At Manglai we help companies measure and manage their environmental indicators, including their water and carbon footprints, with clear dashboards and tailored analysis to support decision-making. Discover how Manglai can help you.