Water is essential to life, without it there would be no life possible on earth. The fact is simple, all living beings need water to exist.The geological nature of the land has a determining influence on the chemical composition of the water retained. At any moment, water is in contact with the soil in which it stagnates or circulates: a balance is established between the composition of the soil and that of the water. This chapter deals with the organoleptic properties and the physical-chemical parameters of the water in order to give a clear idea of the potability of the waterIn order to monitor and interpret the quality of water a bacteriological analysis gives an aid concerning the potability, but the water of exclusively underground origin, suitable for human consumption, microbiologically sound and protected against the risks of pollution.