The notion of a water ethics has only emerged over the past 10 years. It is mainly motivated by environmental concerns and the observation of water conflicts. This chapter focuses on the ethical aspects of human interventions into water systems. It describes cultural, moral and religious attitudes towards water and reviews the state of the art in this field. Its main objective is to conceptualise water ethics on the basis of the philosophical approach of discourse ethics and to draw conclusions for ethically responsible interventions into water systems and for dealing reasonably with water conflicts. Far from promising “miracles” from water ethics, the specific added value of ethical considerations lies in providing the orientation for ongoing debates on water challenges by not only applying substantial principles, but by offering suitable procedures as well.