The evaluation of quality for drinking water produced in softening plant of Libyan Iron and Steel Company in Misurata were studied at four sites in distribution network form January to June 2013. Some physicochemical parameters were measured such as, Temperature, EC, pH, TH, Ca-H, Cl-1 , SO4 -2 ,TA ,HCO3 -1 and Fe. These parameters used in indices calculation in this study. Fives indices such as Langlier Saturated Index (LSI), Ryzer Stability Index (RSI), Puckorius Scaling Index (PSI), Larson-Skold Index (LI) and Aggressive Index (AI) are used to know the state of equilibrium in water inside the network. LSI ,RSI ,PSI ,LI and AI, calculations assigned that water was not able to form precipitate, which might be a cause of corrosion inside the pipes