The role of ethics in water resource management can be complex and confusing in the context of the engineer’s role in providing safe drinking water to the public. The primary responsibility of an engineering professional is to protect public health and safety. However, engineering professionals also have a responsibility to their employers or clients, to their families, to themselves, to the environment, and for Civil and Environmental Engineers, to “strive to comply with the principles of sustainable development in the performance of their professional duties.” This chapter provides a discussion of ethics with Illustrative Examples specifically focused on drinking water production and safe drinking water supply. Topics covered include the ethics of water access, the do’s and don’ts, integrity, moral issues, guardianship, engineering and environmental ethics, and future trends in professional ethics. An applications section provides three Illustrative Examples related to applied ethics issues common in the water sector.