Fresh water, resource that we thought inexhaustible, is rare and often difficult to take. According to most recent data' less than 1% of all fresh water on the planet is easily accessible to human beings. But this small proportion could be enough if the geographical distribution of this resource were better balanced on the planet. At present, 1,2 billion inhabitants, one out of five, does not have access to this so vital fresh water. The lack of water is also related on the demographic growth and pollution. This reality is particularly true in the case of the People's Republic of China. With a population of more than one billion and an increase of twelve million people per year, China cannot provide fresh water of quality to all its inhabitants. Since the economic reform of the end of the 1970's,the cities, the industries and the farmers pour without slackening enormous quantities of untreated water in the environment, which contributes to contaminate the fresh water reserves of this country. This pollution generates serious environmental and economic consequences which are added to the natural disasters that strike the country regularly. To cure these complex problems, great projects such the construction of the Three Gorges dam, which will be the largest dam in the world, were initiated. This project is the subject of an analysis in the scope of sustainable development for China. This analysis accounts for the social, economic and environmental impacts this mega project causes.