Cornelis Johannes (Kees) van Leeuwen, PhD, is Chief Science Officer and Principal Scientist at KWR, and Professor in Water Management and Urban Development at Utrecht University (UU) in the Netherlands. He studied biology and published more than 200 reports and publications, two editions of a book on Risk Assessment of Chemicals, and co-edited the Urban Water Atlas for Europe. He worked at the European Commission as Director at the Joint Research Centre (JRC) in Italy. Over 1992-2007 Kees held a part-time professorship in Biological Toxicology (environmental risk assessment) at UU. Between 1980 and 2001 he worked at three Dutch government ministries in the fields of water, chemicals, health and the environment. He has been a member of various policy and expert groups in the Health Council of the Netherlands, the International Rhine Committee, European Commission, OECD, UN, and the European chemical industry. Currently he coordinates the City Blueprint Action Group of the European Commission: http://www.eip-water.eu/City_Blueprints. His involvement in recent EU research projects includes: TRUST (TRansitions to the Urban Water Services of Tomorrow; finalised in 2015), DEMOWARE (water reuse), DESSIN (ecosystem services), BlueSCities (making water and waste smart) and POWER (sharing knowledge of water scarcity, security, quality and water consumption-related issues at different EU local authorities).