Many developing countries struggle with the most appropriate way by which to ensure that sufficient resources are available, in a sustainable manner, for the provision of water services. This problem is not new. Rather, it is one which most societies have faced in the past, some with considerable success. This paper considers the case of the hydraulic civilisation of ancient Sri Lanka, not from the perspective of its engineering feats, which are well-known, but from the management aspects of its irrigation system. It details how the ancient Sri Lankans devised a two-tier system which, although it had engineering and economic inefficiencies in its physical structure, was perfectly suited to the level of social capital available at the time. Given that social capital is precisely what limits many developing countries, this suggests that ancient Sri Lanka may provide lessons for water resource management which may have application in developing countries today.