The Nile is the main source of drinking water in Egypt. Alexandria water Company (AWCO) depends on the surface water only as canals fed by the Nile River. AWCO has 8 water treatment plants (WTP), 6 of which are located on Mahmoudia canal. AWCO has a monthly comprehensive program to survey canals supplying water to Alexandria water treatment plants (WTP), where all parameters of Mahmoudia canal and drain discharges are measured. This study was carried out during the period from March 2008 to Jan. 2010 and the program is still implemented until now. AWCO regularly monitors the water quality in the canals in the Rosetta branch of the Nile, all the way up to the Delta Barrage near Cairo. The water quality in Mahmoudia canal is stable at a manageable level. The raw water of WTPs has faced serious problems that are affected by the increasing free ammonia and nitrite in winter season. Many corrective steps (hourly free ammonia detection, break point of chlorination and prefiltration powdered activated carbon installation) were taken to overcome these problems. The main objective of this study was to identify long term feasible solutions for the drinking water quality problems on the basis of physical and chemical water parameters. The which are corrective actions had reduced the free ammonia values by more than 75% for WTPs distributed drinking water all over the years.