People and ecosystems require both an adequate quantity of water as well as an adequate quality of water. Therefore, it is urgent to assess where water quality is inadequate or under threat and to incorporate the need for good water quality into the concept of water security. This report focuses on water quality and its relation to development objectives such as health, food security and water security. To make this connection, the report reviews important water quality problems in surface waters including pathogen pollution, organic pollution, salinity pollution and eutrophication. The focus is on three continents: Latin America, Africa, and Asia.