Assessing Groundwater Quality: A Global Perspective: Importance, Methods and Potential Data Sources

Assessing Groundwater Quality: A Global Perspective: Importance, Methods and Potential Data Sources

World Water Quality Alliance (2021). Assessing Groundwater Quality: A Global Perspective: Importance, Methods and Potential Data Sources. A report by the Friends of Groundwater in the World Water Quality Alliance. Information Document Annex for display at the 5th Session of the United Nations Environment Assembly, Nairobi 2021


This perspective paper by the Friends of Groundwater (FoG) group aims to give a compelling argument for the importance of groundwater quality for human development and ecosystem health. It also provides a global overview of the current knowledge, with focus on data coverage, gaps and technological advances. It is a building block towards a future global assessment of groundwater quality as part of the United Nations Environment Programme (UNEP) World Water Quality Assessment (WWQA).

Groundwater is an essential global resource and provides the largest store of freshwater, apart from the ice caps. Current groundwater abstraction represents 26% of total freshwater withdrawal globally, to supply almost half of all drinking water and 43% of the consumptive use in irrigation. In arid and semiarid regions, groundwater is the only reliable water resource. In the environment, groundwater makes an important contribution to river flow and groundwater dependent ecosystems. For drinking water supply, one of the advantages of groundwater is that it is naturally protected from many contaminants. With drought and climate change, people in water-scarce areas will increasingly depend on groundwater, because of its buffer capacity and resilience to rapid impacts. However, groundwater quality, as well as quantity, may be impacted by climate change.

A global groundwater quality assessment is needed because human activities and climate variability increase the pressure on groundwater resources, but it is an invisible resource that remains out of sight and out of mind for most people. Protection of our groundwater resources is necessary for protecting human health, maintaining food supplies and conserving ecosystems. Many regions and countries rely on naturally clean groundwater as advanced water treatment is economically infeasible. Knowing where to source clean groundwater, as well as understanding threats to this resource, is therefore important.

The principal objectives of this perspective paper are to present the importance of groundwater to meet the Sustainable Development Goals (SDGs), notably SDG3, SDG6 and SDG7, describe the threats to groundwater quality from anthropogenic and geogenic contaminants, discuss the challenges of providing a global overview of groundwater quality, present key messages to summarise current knowledge and capacity and outline a Work Plan to develop a global groundwater quality assessment network, including protection and management of groundwater quality.