Vietnam is still today one of the poorest countries in the world. For some years now, it has nonetheless represented a pole of economic development in South East Asia, thanks to a government policy of liberalisation of production facilities. Economic expansion results in an annual growth rate of the Gross National Product of more than 8%, and a metropolitan concentration of activities (Ho Chi Minh City (HCMC) accounting for 30% of foreign investment and Hanoi 14%). Within this framework, Vietnamese cities are confronted with extremely serious problems connected with population increase and degradation of natural resources. Ho Chi Minh City, the metropolis of South Vietnam, has more than 5 million inhabitants. Economic expansion is marked by the establishment of a great many industrial, commercial and service companies. Another aspect of urban reality, the population density is very high (more than 23,000 inhabitants per square kilometre), working-class housing conditions are of very low quality and public networks do not meet the population's needs. Research is currently being carried out by the Environmental Committee of HCMC and the EPFL (Swiss Federal Institute of Technology) in order to establish the relationship between development of the precarious habitat and pollution of the urban water supply. An initial observation may be made: Water represents a key element in the development of HCMC. The city is intersected by canals and rivers, used as a dumping ground for all the industrial and domestic waste, a dwelling place for the most destitute families (makeshift housing on piles), traffic routes for waterway transport and market gardening areas. The question of water utilisation arises because the level of contamination recorded, whether in the conveyance circuit, its domestic use or at the drainage stage, exceeds generally accepted hygiene standards, and constitutes a risk for the population's health. It is essential that measures should be taken, particularly in the precarious habitat areas where the population lives at the limit of absolute poverty. According to the survey conducted on the basis of 600 households in two working-class areas, 42% of the active population have unofficial jobs, and the average monthly household income is in the order of 12 US dollars. Under conditions such as these, it is extremely difficult for families to invest in housing and improving the environment. Innovative forms of dialogue between public authorities, the people's committees which exist in each subdistrict and the population must form the basis of simple solutions aimed at the creation of jobs and the rehabilitation of these areas.