1 This document specifies guidelines for technical aspects, tools and good practices for the management of assets of wastewater treatment plants, sludge treatment facilities, pumping stations, and retention and detention facilities in the wastewater system to maintain the value of existing assets. NOTE1 For simplicity in reading this document, reference to wastewater treatment plants includes all the asset types described above.For further guidance on wastewater networks see ISO24516-3. NOTE2 For simplicity of interpretation of wastewater system assets, the management of pumping stations and retention and detention facilities in the network, excluded from ISO 24516-3 , is addressed in this document irrespective of where these assets are sited in the wastewater system.This document is focused on the assets in wastewater systems typically owned or operated by wastewater utilities that are expected to meet users’ needs and expectations over longer, sometimes multi-generational, periods.This document includes examples of good practice approaches on the strategic, tactical and operational levels.This document is applicable to all types and sizes of organizations and/or utilities operating wastewater systems. NOTE3 Depending on the size and structure of an organization, the utility can decide to what extent it applies the guidance in this document. In any case, the philosophy of this document remains applicable even to small and medium utilities. NOTE4 This includes all different roles/functions for the management of assets within a utility (e.g. asset owner/responsible body, asset manager/operator, service provider/operator).