In many parts of the developing world, the supply of water is limited not so much by nature but by lack of adequate, well-maintained infrastructure. Where an increased supply is necessitated by an increase in population, new infrastructure will obviously have to be built. Because of the high cost of building infrastructure (such as dams, pumping and reticulation systems and treatment works), the first step should be to rehabilitate infrastructure that is in a state of disrepair or not usable. Moreover, governments should ensure regular maintenance of existing infrastructure, since it is less expensive than costly overhaul of dilapidated infrastructure.