The two important components rendering water utilisation possible are; “quantity of the amount of water” and the “characteristic of the water quality”. The need for water can only be completely met if these two components are provided together. The United Nations Environment Programme points out that there is 1,400 million km3 water in the world. However only a very small ratio of this amount (less than 1 %) is usable. Since the usable water amount demonstrates significant changes according to location (position – place) and time (months, seasons, years); “water shortage-water constraint” is experienced in some regions of the world during certain periods. This situation that is on a global scale manifests itself in Turkey also and the water quantity (resources – amount) not uniformly (equally) distributed in the country, causes water shortage to be experienced in some of the regions. In addition to unequal distribution; the change taking place in the rainfall falling on the basins arising from the climate change that has started to make itself felt and hence the change of the water regime; carries the problems derived from the “water constraint” especially in the regions wherein the population and the industrial activity is dense, to the top of the agenda.