In recent years water stress is increased due to the scarcity of water. Water resources are characterized by a very high sensitivity to climatic vagaries, an irregularity in time and a bad spatial distribution and a vulnerability to drought and pollution. In most developing countries, there is often an infrastructure lack of drinking water supplies, especially in rural areas. The populations of these areas resort on archaic methods in order to have a continuous source of water for their own use. In Morocco, the traditional water storage tanks are a particular water supply system, known as « matfia ». In fact, it considered as one of the major drinking water supplies in rural areas, to ensure a resource more at least sufficient especially during drought. These tanks are fed from rainwater and/ or directly from surface water of rivers, and this water is generally consumed by the surrounding population without any treatment. The uncontrolled water storage in such reservoirs leads to a deterioration of their quality.