Due to a rapid population growth, Thessaloniki, Serres and Chalkidiki counties show an increase in agricultural, industrial, manufactural, commercial and tourist activities and therefore, a demand for more water consumption. These activities wipe off and pollute water reserves and therefore, problems of water quantity and quality emerge in these areas. This research deals with the comparative examination of the quality of potable water in the city of Thessaloniki, in the rural areas of Thessaloniki and also in Chalkidiki and Serres prefectures. Conductivity, hardness and the concentration of NO3-, and Cl- are examined. The research reveals a notable presence of nitrate ions in Thessaloniki and Serres plains and a remarkable one in Chalkidiki. Conductivity and Cl-, indicative of the underground water wealth deterioration in a region, appear to be higher in Chalkidiki. There is a demand for immediate integration into a water denitrification program in the Thessaloniki and Serres plains. Additionally, there is a need for developing strategies concerning the management of the water resources in the entire region and especially in Chalkidiki, a region with its particular environmental and developmental characteristics.