Water is a vital resource. Though, in rich countries as well as in poor countries, human pollution can be spotted in the water. There is a strong link between the water we consume and the dirty water we reject in the environment. In rich countries, we are used to clean, desinfect, filter the rejects so a quality water can reach our tap. This method is too expensive for the countries whoch are the most suffering from thirst. Innovative alternatives are needed, in particular in Cambodia, China, Peru and even in France, to make water affordable for every one, to low cost.