Canada faces special challenges as a federal state in managing its vast water resources, many of which are transjurisdictional in nature, shared either with the United States or amongst Canadian provinces and territories. Although the federal government possesses an array of potentially powerful constitutional levers with which to influence specific aspects of water management, it lacks the plenary jurisdiction that would enable it to address water management in an integrated fashion. Under the Canadian constitution, provinces are vested with most of the proprietary and legislative responsibility for natural resources management, including water management, subject to some specific federal interests. However, even recognising the primacy of the provincial role, the federal level of government has taken an exceedingly modest view of its powers. The federal reticence to exercise its authority in waters that are clearly of national interest – especially transjurisdictional watercourses – has arguably hampered the development of effective basin management regimes in Canada. As these waters come increasingly under stress in coming decades, especially in light of the expected effects of climate change, a continuing failure by the federal government to assert a clear role for itself in articulating the national interest in water management may well hamper the effective resolution of emerging water management challenges.