Nigeria has significant renewable water resources; however, the current reality is that most of it is poorly utilized and managed, thus raising important sustainability questions. There are several concerns associated with the water situation in the country such as pollution, flooding, poor drainage infrastructure, etc. All these have dire water-poverty, socio-economic, health and livelihood implications for Nigerians. This discussion paper identifies the absence of a properly functioning regulatory regime in Nigeria’s Water Resources sector – with the ensuing pattern of open-access water use in the country – as a fundamental issue that needs to be addressed. It briefly maps out some specifics of the current situation within Nigeria’s Water Resources sector. Utilising a simple steady-state economic framework that shows the implications of open access use of natural resources, it goes on to explain the sustainability implications of the current water resource use-patterns in Nigeria. Drawing on the points raised, the paper concludes with a few high-level recommendations for water sustainability in Nigeria.