While no hard and fast rules can be applied, municipalities are generally responsible for providing and managing service delivery (water and wastewater), while higher-tier local governments (e.g. regions, provinces) are responsible for competences associated with resources management. A holistic approach is called for in designing the institutional mapping, because some roles and responsibilities can complement with or neutralise each other at central and sub-national levels. There is a diversity of situations across OECD federal and unitary states in terms of the institutional organisation of water policy. On the one hand, some federal countries (United States, Canada, Belgium) have delegated many water responsibilities to lower levels of government, while in other federal states (Mexico, Australia) the central government still plays a strong role (e.g. strategic planning, regulation, etc.)