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Knowledge category: Projects

City Water Circles: Urban cooperation models for enhancing water efficiency and reuse in Central European functional urban areas with an integrated circular economy approach

Updated on 18.11.2022

The City Water Circles project aimed to help municipalities reform outdated urban water infrastructure systems by applying a circular economy approach, which offers many economic and environmental benefits. It did so by promoting a water saving culture and adopting urban rainwater harvesting and utilisation as well as greywater recovery measures.

Acronym: CWC
Countries: Croatia, Germany, Hungary, Italy, Poland, Slovenia
Start and end date: 01.04.2019 - 31.03.2022
Budget: 2 004 405 EUR
Funding source: Interreg Central Europe

More information

Climate-change-induced hydrological risks are making central European cities increasingly vulnerable to urban floods, while also exacerbating water scarcity problems. Coupled with growing drinking water consumption and rising amounts of wastewater to be treated as a result, this threatens the safety of future water supplies. City Water Circles aimed to promote a water saving culture, including the use of non-conventional water resources. It also took the lead in adopting rainwater harvesting and utilisation and greywater recovery measures at city level.

The project partners joined forces to create a knowledge base for urban circular water management. This knowledge was made available as digital learning resources. Together with local stakeholders, the partners also co-developed a set of innovative methods and tools for Central Europe, including cutting-edge technological and nature-based solutions, smart governance tools exploring novel cooperation, and financing schemes. The project involves the following cities: Budapest (Hungary); Bydgoszcz (Poland); Maribor (Slovenia); Split (Croatia); and Turin (Italy).

Relevance for Circular Systemic Solutions

The project aimed to contribute to building a knowledge base for urban circular water management. It set up innovative methods and provided an interface for a variety of stakeholders, including public authorities, water suppliers, agencies and non-governmental organisations. The project also developed the ‘Transnational online handbook on circular urban water management and use’. This is a toolkit for city decision makers, covering information about smart planning, governance, engineering, and digital solutions for water saving and water reuse.

Main results and lessons learnt

The project produced several useful outputs:

1. The Transnational online handbook on circular urban water management and use - This e-handbook consists of four thematic catalogues:

  • Thematic catalogue 1: ‘Smart tools for assessing the potential of urban water use’
  • Thematic catalogue 2: ‘Innovative engineering and nature-based solutions for circular water consumption’
  • Thematic catalogue 3: ‘Promoting smart water management tools’
  • Thematic catalogue 4: ‘Novel digital tools promoting water efficiency among citizens/consumers’. The handbook is directed at city decision-makers to support them in their planning of future investments in urban circular water measures.

2. Training materials on circular urban water management - This document presents a model for a local competence-building workshop with relevant stakeholders. The first module of the training (half a day) focuses on creating a shared knowledge base and a shared language on circular urban water management areas of intervention: water governance; water efficiency and losses reduction; rainwater management; and greywater recycling.

The second module of the training (one day) is mainly devoted to a group game on case studies, exploring structured involvement of stakeholders to build a shared vision and the identification of intervention strategies for circular water management in a city. Led by a facilitator, the workshop gives participants experience of how to build a smart water governance process. The active and participatory approach is a key component, as participants, their knowledge, experiences and ideals are the protagonists of the learning process.

3. Examples of innovative solutions in practice:

4. Transnational strategy and policy recommendations for boosting circular water use in the Central European region

Responsible organisation and contact details

City of Budapest, District 14 Zugló Municipality

Contact the project:

Project consortium partners

  • Split water and sewerage company Ltd.
  • Public Institution RERA SD for Coordination and Development of Split-Dalmatia County
  • Budapest Sewage Works Plt. Ltd.
  • Institute for Sustainable Development Foundation
  • City of Bydgoszcz
  • E-Institute, Maribor Water Supply Company
  • Association for Rainwater Harvesting and Water Utilisation
  • Poliedra – Service and consultancy centre at Politecnico di Milano on environmental and territorial planning
  • Turin Municipality


CEAP2 key product value chain

Territories involved


large 500 000-200 000, medium 200 000-50 000, and small cities 50 000-5 000