should remain the last resort, and should only be applied after having carefully considered cheaper alternatives in terms of supply and demand management. A second conclusion is that the private sector can play a useful and important role in funding and operating desalination plants, but only if the above conditions are met. If these conditions are absent, there is a risk that excessive investments in desalination become a drain to the national budget, either directly under public financing or indirectly through implicit or explicit guarantees under private financing. A third conclusion is that desalination technology itself has evolved substantially, making it significantly cheaper, more reliable, less energy-intensive and more environmentally friendly than it was a few decades ago. This is especially true for reverse osmosis, which is gaining a large share of the market outside the Gulf countries which continue to use mainly distillation technologies.