The organisers of the Forum asked all regions involved to make their own specific contributions to the Forum. Responding to this, a WWF4 European Regional Committee was set up in August 2005, on a voluntary basis. The Netherlands Water Partnership was asked to coordinate the European preparatory process. Many organisations that play an active role in the water sector in Europe participated and co-operated in order to produce a joint European representation for delivery at the Forum:

• Astee, the French Water Association
• Austrian Development Agency
• Bosnia and Herzegovina Water Works Association
• Budapest Water Works
• Complutense University of Madrid, Spain
• Cooperative Programme on Water and Climate
• Danish Water Forum (DWF)
• Drainage and Irrigation District “Riviera Berica”
• Dutch Coordination Team 4th World Water Forum 
• European Committee of Environmental Technology Suppliers Association (Eucetsa)
• Eureau, European Union of National Associations of Water Suppliers and Waste Water Services
• EUROPE - INBO
• European Commission
• European Environmental Bureau
• European Investment Bank
• European Union Water Initiative Secretariat (EUWI-Secretariat)
• European Water Supply and Sanitation Technology Platform (WSSTP)
• French Coordination Team WWF4
• French Water Academy
• Global Water Partnership
• Government of Finland
• Global Water Partnership Central and Eastern Europe
• Global Water Partnership Mediterranean
• International Network of Basin Organisations
• International Office for Water
• International Secretariat for Water
• International Water Association (IWA)
• Ministerio de Medio Ambiente, Spain
• Netherlands Water Partnership (NWP) (chair)
• Northern Water Network (NoWNet)
• Organisation for Economic Co-operation and Development (OECD)
• Programme Solidarit? Eau
• Seine-Normandy Water Agency
• Solidarity Water Europe
• Springs Foundation
• Stockholm International Water Institute (SIWI)
• Suez
• Technical University of Kavala, Greece
• Technische Universit?t Hamburg - Harburg (TUHH)
• University of Osnabruck
• Waste
• Water Scarcity Group
• Woman in Europe for a Common Future (WECF)
• Women for Water, Water for Women (WfWfW)
• World Water Council