Since 2006, PATH has investigated how commercial market forces can help extend access to safe water in developing countries and reduce waterborne disease. Promoting household water treatment and storage products targeted to low-income consumers is a key part of the strategy. This project brief summarizes PATH's work in Malawi working with the US Centers for Disease Control and Prevention to assess the effects of an innovative program that promoted chlorine disinfectants for household water treatment to pregnant women seeking antenatal care.