Definition: the water exploitation index plus (WEI+) is a measure of total freshwater use (cooling water is not counted) as a percentage of the renewable fresh water resources (groundwater and surface water) at a given time and place. The indicator is presented as annual average values. Annual calculations at national level, however, cannot reflect uneven spatial and seasonal distribution of resources and may therefore mask water scarcity that occurs on a seasonal or local basis. The data come from Eurostat.

Goal: the water exploitation index plus (WEI+) must remain below 20%.

The Sustainable Development Goals or SDGs adopted by the UN in 2015 include target 6.4: “By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity.

The Federal Long-Term Strategic Vision for Sustainable Development contains objective 34: “Renewable resources, in particular freshwater, will be exploited without compromising the ability of future generations to exploit them” (Belgian Official Gazette, 08/10/2013).

The European Environment Agency, which calculates the WEI+ indicator, considers values above 20% as an indication of water scarcity, while values equal or bigger than 40% indicate situations of severe water scarcity where the use of freshwater resources is clearly unsustainable (EAA, 2025).

The Roadmap to a Resource Efficient Europe furthermore mentions as a milestone that "Water abstraction should stay below 20% of available renewable water resources" (European Commission, 2011).

On this basis, the water exploitation index plus should remain below 20%.

UN indicator: the selected indicator corresponds to indicator 6.4.2 - Level of water stress: freshwater withdrawal as a proportion of available freshwater resources.

Sources

• Belgian Official Gazette: http://www.ejustice.just.fgov.be/cgi/welcome.pl; research on http://www.ejustice.just.fgov.be/doc/rech_f.htm.

• EEA (2025), Water scarcity conditions in Europe, https://www.eea.europa.eu (consulted on 30/6/2025).

• European Commission (2011), Communication from the Commission to the European Parliament, the Council, the European economic and social Committee and the Committee of the regions. Roadmap to a Resource Efficient Europe, COM/2011/0571 final, https://eur-lex.europa.eu.