VEI is an international cooperation between the two largest water companies of the Netherlands: Vitens and Evides Waterbedrijf.

Besides Vitens and Evides Waterbedrijf, VEI has three more participants: WMLWatercompany Groningen and Brabant Water signed a partnership. Together, these partners join forces to fight international water and sanitation problems.

Another important partner for VEI is the multi-sector partnership WSUP (Water and Sanitation for the Urban Poor). WSUP develops commercially viable models to help cities reach everyone with improved water and sanitation services. VEI and WSUP work together on several joint international projects.

Also, VEI works with UNESCO-IHE, the Institute for Water Education in the Dutch city of Delft. The two parties joined forces to increase the effectiveness and impact of capacity building in the international water sector.