The reasoning behind the exploitation of water resources up to now assumed the abundance of this resource and has followed a different model from that adopted for the exploitation of other natural resources such as mineral deposits. It is presumed that water is of more or less uniform chemical composition and has been distributed through a system designed only for potable water. The scarcity of this resource, however, makes it necessary to look at sources of water with hitherto "unacceptable" chemistry. Large-, medium- and small-scale desalination units, in combination with other systems, can play a vital role in the chain of supply by providing the means to match water quality to each user's needs. There are environmental problems to be solved also, which need to address seriously the import-export dynamics of TDS and individual ion species into any quasi-closed system. The paper discusses the problems created by the presumption of abundance and suggests solutions through an integrated water strategy that engages all stakeholders.
