ZerO-M, short for "Sustainable Concepts Towards a Zero Outflow Municipality", is a project financed by the MEDA Water programme of the European Union (EU). This project aims at concepts and technologies to achieve optimised close-loop usage of all water flows in small municipalities or settlements (e.g. tourism facilities). A key idea in ZerO-M is to integrate water supply, wastewater treatment and reuse. Actually it is about abandoning the concept of "waste" water, because on one hand there is no water to waste, and on the other disposal is a poor concept, which so far has proved very unsafe. From a disposal problem we should shift to an asset, which has to be developed. In order to encourage implementation of this concept in real systems ZerO-M is presently building so-called training and demonstration centres on one side, with a great variety of different techniques to be shown and tested, and pilot plants to implement and demonstrate the same techniques under real conditions. First results about greywater in MEDA countries will be discussed. Water demand and saving measures in rural areas of MEDA countries as well as simple potable water substitution techniques will be presented on the basis of studies and implementations of ZerO-M.