Since 2016, the World Bank's Water and Governance Global Practices have been implementing the Policy, Institutional and Regulatory (PIR) Incentives Initiative to gain deeper insight into the dynamics between water supply and sanitation (WSS) sector incentive mechanisms. PIR is a global framework for understanding factors that can contribute to positive sector outcomes at the country level. This knowledge brief uses a PIR framework to provide a snapshot of the experiences of five countries in South America: Argentina, Brazil, Chile, Colombia, and Peru. The brief showcases the wide variety of incentives created by governments to successfully motivate people (as individuals or as part of an institution) to do their part in an integrated PIR system and how a lack of such integration may produce perverse incentives that prohibit the achievement of sector goals. Governments looking to strengthen the WSS sector should, therefore, take a holistic approach to sector reform and one that seeks to align PIR incentives through integrated interventions. This alignment includes harmonization between sector objectives, rules of the game, and mechanisms for implementation. Of critical importance is the financial and human resource capacity of sector institutions. Countries in South America need to move beyond the technical solutions that enabled them to achieve the MDGs and in the process carefully consider the drivers for reform and the best fit for the prevailing institutional context.