The International Water Association (IWA) Specialist Groups for Small Water and Wastewater Systems (SWWS) and the Resource Oriented Sanitation (ROS) held the latest version of the IWA SWWS and the IWA ROS in 2019 Australia. The proposal is to return to hold both conferences – 17th IWA Small Water and Wastewater Systems and 9th IWA Resource Oriented Sanitation – in Curitiba, Paraná State, Brazil. The event is aimed at water and sanitation specialists, researchers, students and companies with solutions for resource recovery and small water and sewage treatment systems. During the event it is intended to bring together participants from different parts of the world, in particular the Americas, Europe and Asia.