Urban wastewater treatment in small rural communities, where technical and financial resources are usually limited,, can pose a problem. Experience has shown that, when treating wastewater in small communities, the solutions used in larger cities are not applicable. In order to solve the problems involved, a number of alternative solutions have been developed, based on small-scale treatment systems which are adapted to the needs of these areas (non-conventional technologies). In Andalusia (Spain), as well as in Morocco, there are a large number of towns with small populations which have insufficient financial resources or management capacity to deal with the problem of their wastewater treatment using the classical treatment systems which, owing to their operational and maintenance costs and the need for qualified personnel, are not feasible in such towns. In Andalusia there is a centre which has become a reference point of urban wastewater treatment in small rural communities both in Europe and in the whole Mediterranean area: the Carrion de los Cespedes Experimental Plant (PECC) in Seville. Here, in a single area covering 35,000 m(2), a number of different treatment systems have been set up, where conventional and non-conventional technologies take pride of place, including combinations of them. On the other hand, in the North of Morocco, the Technological Transfer Centre (CTT) in Tetouan, there is a single area covering 30,000 m(2), with different non-conventional treatments systems. Moreover, there is a cooperation centre where the Andalusian and Moroccan administrations can debate about some subjects related with water in both countries. So in the both PECC and CTT, there is ongoing research to find answers for urban wastewater treatment needs in small communities, which is very important in the Mediterranean area, where the water stress problems and the situation in these population areas need more and more researches and progress in this matter.