Abstract: The aim of this research is to study the potential of scale formation and corrosivity of water resources and the network distribution system of Shiraz in Fars province, South Iran. The Langelier saturation index (LSI) was used to assess the scale formation and corrosivity. The index was calculated based on the principle of calcium deposition. This research was done through 118 water resources samples which include wells and surface water and many different points in the network distribution system during late Summer and early fall, 2007. The mean LSI value for all the samples was 0.417. Although, the results indicated the scaling potential in all water samples, monitoring the corrosion rates was done on a regular basis. Seasonal changes can affect water quality, and therefore the corrosion rates.