This book consists of the hydrogeochemical study of the springs of the Sicilian territory used for drinking water purposes. One of the most important issues in the environmental field is the protection of water resources and in particular the safeguarding of water intended for drinking water use. Water resources need a careful prevention of pollution starting from multidisciplinary studies (geology, hydrogeology, geochemistry, geophysics) to understand the territory in order to highlight vulnerable areas and then plan, where necessary, monitoring activities for the control and protection of the resource. The reference is the Piano Regolatore degli Acquedotti (PRGA) of Sicily, Italy (updated in November 2010), which lists all the springs, subdivided by province (a total of 1014), currently used to supply water to Sicilian aqueducts. With regard to the geochemical part, the studies carried out by the INGV, Sezione di Palermo, for the Water Protection Plan for Sicily (2004-2005) were used as basic data. The study of the chemical characteristics of groundwater is of fundamental importance from a hydrogeological point of view as it allows the origin of the water and its evolution to be reconstructed. Springs as a groundwater resource are of considerable importance in relation to the availability of water resources due to the general decrease in precipitation. In the first part of the book all the existing data (flow rates, geochemical parameters, water quality, etc.) are collected and subsequently transferred to GIS software, after appropriate evaluations on the validity of the acquired data. Considering that the subject is quite delicate and involves various aspects (compliance with regulations, vulnerability of groundwater, anthropogenic pollution, etc.), carrying out a purely scientific study allows groundwater to be placed in a broader context than that of legislation aimed exclusively at compliance with the regulations in force.