While water availability is acknowledged as a significant and present problem that threatens the livelihoods and health of people in many regions, the same is not true for water quality. The World Bank has branded water pollution an “invisible crisis” and stressed that because water quality is often difficult to detect and imperceptible to the human eye, it is being under-monitored all over the world.

With increasing human population, economic and agricultural development and climate change, water quality is increasingly coming under pressure. Yet, clean water is vital for our societal needs – such as public health, energy generation and crop production – and for protecting ecosystem health. The United Nations Sustainable Development Goal (SDG) 6.3 recognizes the role of inadequately managed wastewater in this crisis and requires countries to halve the amount of untreated wastewater being discharged into the environment by 2030.

The authors of a new study, published in the journal Nature Communications Earth & Environment, have now developed a comprehensive new water quality model to map hotspots of water problems, as well as to help understand what the consequences of attaining SDG 6.3 would be in terms of water quality around the world. In this high-resolution model they consider current and future surface water quality in terms of its salinity, its levels of organic pollution and its pathogen load, as indicated by fecal coliform abundance.