What is a water footprint?

The availability of freshwater is under growing pressure due to global demand, climate change and population growth, which is expected to reach around 9.7 billion people by 2050, according to UN projections. According to UN agencies, between two and three billion people experience water scarcity at different times of the year, and the proportion of affected cities could double by 2050, with up to 2.4 billion people facing urban water stress unless current trends change. 

This is compounded by the fact that the water cycle is becoming increasingly irregular due to floods and extreme droughts, making it more difficult to manage this vital resource for agriculture, industry and households.

The products we use, the clothes we wear and the food we consume all require water for their manufacture or production. Statistics show that a long shower in a high-income country can consume between 100 and 150 litres of water, exceeding the 50 to 100 litres that the World Health Organization considers sufficient to meet basic daily health and hygiene needs.

All of this raises a key question: how can we manage an essential resource in a context of growing global pressure?

What is a water footprint and what is it used for?

The concept of the “water footprint” was introduced in 2002 by Arjen Hoekstra while working at the IHE Delft Institute for Water Education (then UNESCO-IHE). In 2008, as interest from industry and policymakers grew, he co-founded the Water Footprint Network ↗ together with partners from the business, academic and public sectors to promote research and the sustainable use of freshwater worldwide.

A water footprint can be used to measure the water consumption of virtually anything: from manufacturing a pair of jeans or tracking a company’s annual activities to calculating the total consumption of an entire country. Its purpose is to raise awareness of the enormous volumes of water required by our production processes and lifestyles, encouraging rational and sustainable use.

Types of water footprint

According to the Water Footprint Network, the water footprint is made up of three elements, depending on the source of the water:

Green water footprint

Rainwater stored in the soil and used by plants through evaporation and transpiration. It is especially relevant in agriculture, forestry and horticulture.

Blue water footprint

Water extracted from surface or groundwater sources that is consumed during production, incorporated into products or returned to water bodies. Irrigated agriculture, industry and households typically generate blue water footprints.

Grey water footprint

The volume of freshwater required to dilute pollutants generated during industrial or agricultural processes until water quality standards are met.

What Iberdrola is doing to protect water

Protecting nature and ensuring the sustainable use of resources are fundamental pillars of Iberdrola’s sustainability strategy. To contribute to more efficient water management, the Group is promoting initiatives such as:

• Reducing water intensity in electricity generation, with the goal of lowering it by 40% between 2025 and 2030.
• Reducing specific water consumption, with a voluntary target of 63% between 2021 and 2030, measured in cubic metres per GWh produced.
• Accelerating the transition towards renewable energy, replacing thermal generation technologies that are more water-intensive.
• Gradually closing facilities with greater water impact, which has already made it possible to significantly reduce the volume of water used to generate electricity.
• Collaborating with local authorities and organisations to ensure the responsible and shared use of water resources in the areas where the company operates.

What factors increase a country’s water footprint?

A country’s water footprint does not depend on a single factor, but on a combination of structural variables:

• Climate: water availability and evaporation directly influence water demand.
• Agricultural model: intensive irrigation generally increases water consumption compared with rain-fed systems.
• Consumption patterns: diets that require more water resources, such as high meat consumption.
• Level of industrialisation: industrial production increases water demand.
• Technological efficiency: more advanced irrigation and production systems reduce consumption.

Examples of countries with particularly high water footprints

Mongolia recorded a water footprint of close to 10,000 litres per person per day in studies by the Water Footprint Network ↗. Its dry continental climate, combined with the importance of livestock farming in its economy and its relatively small population, makes per capita water consumption especially high.

A similar situation can be found in Niger, whose per capita water footprint stood at around 9,600 litres per day. In this case, high temperatures, irregular rainfall and a strong dependence on agriculture and livestock farming in an arid environment mean that food production requires large volumes of water.

Bolivia also ranks among the countries with the highest per capita water footprints, at around 9,500 litres per day, influenced by the importance of agriculture and livestock farming, as well as highly diverse geographical and climatic conditions that affect productivity and access to water resources.

In other economies, the main factor is not the footprint per inhabitant but the total scale of consumption. China has one of the largest absolute water footprints in the world, at nearly 1.4 trillion cubic metres of water per year, around 16% of the global total according to data compiled by the Water Footprint Network based on research conducted for UNESCO-IHE.

India presents a similar situation, with a total water footprint of close to 1.1 trillion cubic metres per year. Its large population, the importance of irrigation and strong demand for food and raw materials make water an especially strategic resource.

Water footprint or water impact?

Although often used interchangeably, there are differences between the concepts of water footprint and water impact:

• Water footprint: measures the total volume of water used directly and indirectly in goods and services.
• Water impact (International Organization for Standardization 14046): evaluates the environmental impact associated with water use, not only its consumption.

Both approaches are complementary in helping us better understand the impact of water use.

How to reduce your water footprint 

Small daily actions can significantly reduce water consumption:

Food

• Reduce meat consumption, especially beef.
• Avoid food waste.
• Prioritise local, seasonal products with lower water impacts.

Consumption and clothing

• Choose durable, high-quality garments.
• Reduce fast fashion consumption.
• Look for product transparency or environmental certifications.

Energy at home

• Optimise hot water use.
• Use energy-efficient appliances.
• Adopt responsible consumption habits.

Mobility 

• Prioritise walking, cycling or public transport whenever possible.
• Share vehicles to make better use of resources already produced.
• Charge vehicles using electricity from renewable sources whenever possible.
• Replace short-haul flights with rail travel where viable alternatives exist.