This policy brief outlines whether and when integrated water resource management (IWRM) is relevant to WSUP (Water Supply for the Urban Poor). IWRM is internationally recognised as a good idea, but it can seem to be a confused concept, to both to policy makers and practitioners. It is really a synergy of sustainability, good water management, equity and collaboration, but it is criticised for lacking an operational definition and failing to sustain lasting change. For an overview of IWRM refer to “Pragmatic but Principled” 1 (Heath, 2010i ). This brief reviews the situations when IWRM is relevant to water supply and sanitation services in peri-urban areas, outlines why the process of IWRM is generally not relevant to WSUP then summarises the benefits of incorporating the principles into WSUP’s work and how to do this.