The purpose of this study is to study the effect of water quality and quantity of raw water on advanced and conventional treatment processes. We are using data of water quality and quantity to investigate difference of quality of treated water in water treatment plant. Finally we compared items of ware quality ( turbidity, free residual chlorine, total hardness, conductivity, pH, NH3-N) whether passed the Taiwan¡¦s national standard of drinking water or not. We are hoping the treated drinking water will all fit the goal of high quality. Results show that high variation of turbidity was found from May to October in every year. The high turbidity was frequently occurred from 9.9% (2008) to 39.5% (2010). It indicated the worsen trend of water quality of raw water is increased yearly. In all monitoring items of water quality, turbidity, conductivity, NH3-N was greatly influenced in seasons from June to September. The rest items had no significant affect by season¡¦s variation. The removal efficiency in items of water quality of advanced and conventional WTP we found there were high value at hardness and TDS with 49.3% and 43.3% respectively. These items, water quality of treated water (such as turbidity, free residual chlorine, total hardness, conductivity, pH, NH3-N), were all pass the current drinking standard in Taiwan ( i.e., turbidity¡Õ2NTU¡BTDS¡Õ500mg/L¡B6.0¡ÕpH¡Õ8.5¡B0.2mg/L¡Õfree residual chlorine¡Õ1.0mg/L¡BNH3-N¡Õ0.1mg/L ).