This paper aims at presenting a point of view that, in the author's opinion, is not considered sufficiently in discussion forums regarding water treatment. This point of view is the one provided in Spain by the so called contractor-operator companies, which are the ones with most practical experience in Spain. From this business point of view, it is reasoned that the water reuse market can be important in the rnedium and long term because of its volume and the fact that there exists no social-political refusal. So that this market could develop rapidly and without great obstacles, a series of conditions required for it are indicated: a legal framework, quality guidelines, and a basic definition of treatments according to technical considerations and not ideological ones. Finally, it is stressed that treatments should be robust and reliable, and in addition should permit a standardization in the areas they are to be applied.