Water circularity: a matter of urgency 

From pollution and overconsumption to droughts, water resources are facing a severe decline in terms of quantity and quality. Implementing water circularity is becoming increasingly urgent.

For several decades now, experts worldwide have been warning of the 'water crisis''. However, the term 'crisis' implies a temporary phenomenon followed by a return to normal. This is no longer the case today, as numerous river basins worldwide are already suffering irreversible damage. This is why the UN now speaks of “global water bankruptcy”. According to a report by its University Institute for Water, Environment and Health published in early 2026, “the Earth has entered an era of global water bankruptcy because long-term water consumption exceeds renewal of the resource” (see box). Some, including Anne Le Guennec, CEO of the Water Technologies Zone at Veolia, even estimate that freshwater demand could exceed supply by 40% by 2030.

This concept of water bankruptcy therefore refers to a state where water use and pollution have exceeded renewable supplies, and where natural capital (including aquifers, wetlands, soils, rivers and glaciers) is altered irreversibly or at a prohibitive cost. In other words, the concepts 'water stress' and 'water crisis' are no longer enough to describe the global situation.

Yet, while it is possible to emerge from a crisis, recovering from bankruptcy requires a complete change of model. Developing water circularity is central to this transformation; it is more necessary than ever, both from an environmental perspective and in terms of security and social justice.

The planet is now living beyond its water means

According to the report by the United Nations University Institute for Water, Environment and Health:

– Surface waters are shrinking. More than half of all large lakes have seen their levels fall since the 1990s.

– Over the past five decades, 410 million hectares of wetlands have disappeared, causing an estimated loss of ecosystem services of more than $5.1 trillion per year.

– 70% of the main aquifers show a sustained decline. Groundwater provides 50% of domestic water consumption and more than 40% of irrigation water.

– Many regions worldwide have lost more than 30% of their glacial mass since 1970.

– Water reserves in agricultural regions are being depleted. Agriculture accounts for 70% of freshwater withdrawals. More than half of global food production is located in areas where water reserves are declining or unstable.

– An increasing proportion of water is no longer drinkable or economically viable (e.g. pollution due to untreated or insufficiently treated wastewater, agricultural runoff, industrial and mining effluent and the salinisation of many river basins).

– Almost three-quarters of the world’s population live in countries facing water insecurity.

A key topic on the agenda of the 2026 World Basin Summit

The topic of circularity took centre stage at the World Basin Summit, organised by the INBO in Rio de Janeiro in mid-June. In fact, the discussions focused on five major strategic issues, including the critical need to accelerate the transition to a circular water economy. The international event concluded with a key message: “Faced with the accelerating impacts of climate change and the need to adapt to them, a wide range of strategic, technical and operational solutions must be discussed and shared at all levels to ensure water security and strengthen regional resilience.”

Greater water circularity: yes, but how?

Today’s challenge is to align demand management as effectively as possible by reducing and optimising the use of blue water (surface water) and green water (groundwater) with the development of alternative resources, including non-conventional water (NCW)⁽¹⁾ and desalination.

Within non-conventional water (NCW) sources, wastewater reuse is expanding but still requires significant effort. While 8% of treated wastewater is recycled globally, the rate in France was barely 1% at the start of the 2020s. In response, the French government's 2023 Water Plan aimed to increase this rate to 10% (mainly by lifting regulatory barriers), in particular through the implementation of 1,000 new non-conventional water recovery projects by the end of 2027. By the end of February 2026, 508 additional installations had been established across 164 wastewater treatment plants and 344 agri-food production sites.

However, water circularity can take many other forms.

In the industrial sector, it mainly involves closed-loop reuse, such as closed-loop cooling circuits and water recovery from dewatering operations (e.g.: the agri-food, pharmaceutical and cosmetics industries) or on-site wastewater reuse. This recovered water is mainly used to supply utilities (such as boilers and cooling towers) and for cleaning-in-place operations. Since December 2023, a European project ('Resurgence') has been investigating industrial water circularity and its contributing solutions. It aims to develop new, more efficient circular industrial water systems that could help achieve climate neutrality goals alongside competitiveness. The project, which runs until the end of 2027, is based on three sector-specific case studies (paper, chemicals and steel) and a study focusing on synergies between urban wastewater treatment and industry.

For local authorities, water circularity takes on a completely different dimension, as existing water and sanitation systems are showing certain limitations in view of the necessary paradigm shift. This is exactly why the Horizon Europe 'Solucir' project was launched this year to “combat water scarcity and climate challenges by catalysing the large-scale adoption of circular and decentralised water solutions”. The basic principle is to demonstrate that, given the ageing and inflexible nature of existing centralised systems, decentralisation can build resilience and promote resource recovery.

Within this framework, 16 partners from 10 countries, covering the entire water value chain, will collaborate over four years to build the foundations for a more resilient, circular and sustainable water supply for future generations across Europe and beyond. This quest for decentralised and circular water systems is based on an empirical and technological approach that combines the analysis of 23 inspirational pilot sites to identify best practices and conditions for success, the implementation of five 'pathfinding studies' across Europe and a transferability study in South Africa, the deployment of cutting-edge digital tools, structuring risk assessment frameworks and building viable business models. As the project pilot highlights, choosing circular and decentralised water management solutions is driven by a determination to manage the expansion of urban populations and infrastructure gaps, particularly in peri-urban areas.

More broadly, catalysing the widespread adoption of circular water solutions should help strengthen the sustainability of the sector in Europe.

1) Non-conventional water:  rainwater, recycled water from raw materials, recycled process water, greywater, water from public or commercial swimming pools, industrial process wastewater, treated wastewater.