Water management entered the 21st century unresolved despite being a key resource for survival of humanity. Though considerable attention and advancement occur in its management this resource is still far from achieving sustainable management. In this paper the authors, out of the work of two funded CNPq projects and the work of Veiga (2007), reflect upon the work developed in the four countries - France, Brazil, Portugal and Mozambique - exploring lessons from efforts develop to improve the management of this resource. Through understanding and comparing the four contexts the authors establish a debate for figuring out the underlying reasons for the controversies generated which have quite unexpected and perverse consequences that affect and waste this resource. Through the study of case studies in each of the Portuguese-speaking countries the authors found commonalities and differences that constitute a rich learning process worth understanding to the ones responsible for the setting of future water management policies. If it is true that drinkable water is scarce, it is not less true that if we do not learn from the diverse experiences and correct water management policies the survival of humanity is at stake