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A river surrounded by vegetation

What is a water footprint and why is it important?

An environmental indicator to consider

Did you know that everything we consume requires water? From the food that we eat to the clothes that we wear, it all requires this fluid at some point in the cultivation or production process.

Reading time: 9 min

What is a water footprint?

A water footprint is an environmental indicator that measures the volume of fresh water needed to produce the goods and services demanded by society. It enables us to determine the magnitude of the impact generated by human activity and obtain objective data. More sustainable decisions can then be made to reduce the consumption of water and increase water efficiency.

The concept of "water footprint" was coined in 2002 by the researchers A. Hoekstra and M. Mekonnen from the University of Twent in The Netherlands. According to the Water Footprint Network's ranking, currently the top five countries with the largest water footprint per capita are:

  1. Mongolia: 10,000 liters of water per person per day
  2. Nigeria: 9,600 liters
  3. Bolivia: 9,500 liters
  4. United Arab Emirates: 8,600 liter
  5. United States: 7,800 liters

According to official organizations in Spain, the main productive sectors (agriculture, livestock, forestry, industry, etc.) across its different regions represent an "intense" use of water, amounting to 6,700 liters per person per day.

So, what is known as a water footprint? In order to calculate this, the internal water footprint (the water used for producing goods and services consumed by the population) and the external water footprint (the water used in other countries to produce good and services) were taken into account.

Types of water footprint

If we look further into it, there are three types of water footprint that we are aware of depending on where the water comes from:

Close-up of water drops on a leaf

Green footprint (rain)

This is the water that is superficially stored in the soil or on plants such as water from rain or snow. A green water footprint calculates the volume of water used in agricultural, horticultural, and forestry products. 

A lake with mountains in the background

Blue water footprint (fresh water)

This is the water stored in large masses, from surface or groundwater sources, such as rivers, lakes, and aquifers. A blue water footprint calculates the volume of water consumed resulting from irrigated agriculture, industry, and domestic use.

Operator inspecting a water source

Gray water footprint (water quality)

This last type refers to the volume of fresh water required to dilute the load of pollutants from production processes until a concentration below the maximum allowed by the regulations in force is achieved.

How is a water footprint calculated?

There's no mathematical formula that can be applied to all cases to determine the water footprint of an individual consumer, good, service, or specific geographical area. Depending on the calculation to be performed and the activity sector at stake, there are two methodologies that can be applied: 

Hands holding a drop of water

On the one hand, the Water Footprint Network's methodology is based on calculating the water used (including the water needed to dilute the discharge of pollutants to meet environmental standards). In this case, there are three different types of water footprint as previosuly seen: blue and green for quantifying the consumption of water and gray to calculate the pollution level.

On the other hand, the ISO 14044 standard's methodology is an environmental tool for assessing the impact a product, packaging, or process has throughout its entire life cycle. It's divided into four phases:

  1. Goal and scope definition
  2. Inventory analysis of the water footprint
  3. Impact assessment of the water footprint
  4. Interpretation of results

Regardless of the methodology chosen to calculate the water usage, it's very important to check each link of the production and supply chain to ensure that the results are as objective as possible. Thanks to these calculations, a realistic representation is obtained in order to take specific actions aimed at achieving a more sustainable use of water. 

How to reduce your water footprint

Are you worried about saving water? Simple actions like turning off the tap or reducing food waste are things we can all do, and they can cut our water footprint considerably. As consumers, we can adopt a number of simple habits to lower water consumption in all areas of our lives.

A child filling up a glass with water

Tips for reducing the water footprint of individual consumers:

  • Reduce the amount of water used to shower and turn off the tap while soaping up, brushing your teeth, or shaving. Also, eco-friendly shower heads, toilets, and taps that can regulate the water flow can be installed.
  • Commit to water efficiency. Choose appliances certified as energy-efficient for the home, and turn them on only when they are fully charged.
  • Choose responsible consumption and a more sustainable diet that is rich in fruits and vegetables and reduce food waste.
  • Consume recycled products.
Three individuals having a conversation

Tips for reducing the water footprint in companies:

  • Develop an environmental quality system
  • Promote recycling, reusing, and circular economy principles
  • Digitalize processes to avoid using paper
  • Work with suppliers committed to reducing the water footprint
  • Conduct awareness campaigns to ensure all company employees take part 
Repsol Water Tool chart

Repsol and water management

At Repsol, we know that water is an essential resource for life, and we are therefore committed to using it efficiently, preventing risks, and minimizing impacts. We also work to reduce our carbon footprint and drive the energy transition. 

We use the Repsol Water Tool (RWT) to assess the risks associated with water. This enables us to identify the businesses and facilities where a greater management effort must be made and the needs for action that are a priority.