It is will known that drinking water is very important and essential for human life. Water participates in muscle, lungs, brain and mostly in blood. If water is not good or polluted, man health will be affected and it will causes many diseases. The present work was conducted to evaluate the quality of the drinking water which were withdrawn from two water stations in Mansoura city.
Samples were taken from each water station, from the input and other from the output. The water samples were physically and chemically analyzed for the following parameters: temperature, PH, carbonate, bicarbonate, chloride, calcium, magnesium, calcium hardness , magnisum hardness , total hardness ,electrical conductivity (EC), ammonia, nitrate, and organic matters. High levels of HCO3^-, Cl^- and NO3^-  for new Mansoursa station  raw water with the average values of 240.95 , 37.30 and 68.6 ppm respectively. These  values decreased to 183.1  and 58.8 ppm for HCO3^- and NO3^-  in treated water,  respectively,  while Cl^-content increased to be 44.40 ppm. Shark- El-Mansoura station raw  and treated water  samples have the same high values of Ca⁺⁺ (96.64 ppm)  and Mg⁺⁺ (36.24 ppm  ) ,while the level of NO₃^- was lower than the first one (49.6 ppm).
                Organic Matter (OM) contents of raw and treated water samples of new Mansoursa station were 0.033 and 0.02 gm/100ml respectively. Although  the values of OM of samples obtained from the other station decreased to be 0.026 and 0.013 gm/100ml, respectively . Pesticides residues were also determined in the treated water samples using GC chromatography in the presence of 19 standards pesticides  compounds.  Microbiological examination using the same water samples includes: Total viable count (TVC), pathogenic bacteria ( coliform group e.g. Escherichia coli and  spore-forming bacteria (SFB). Moreover green and Blue green algae were also examined  .
                The results revealed that treated water of Shark- El-Mansoura station is contaminated with bacteria , the (TVC) were ranged from 1.5×10³ cfu/ml to 2.0×10⁴ cfu/ml in both stations . Spore-forming bacteria (Bacillus spp) which  do not pose any health risk for human reached to maximum of 2.0 × 10³  cfu/ml in  Shark- El-Mansoura . All collected samples were found coliform free . Green algae  and blue green algae  were not detected in all the water  samples collected from new Mansoursa station . While samples collected from Shark EL-Mansoura station were blue green algae free , and 130 to 221 unit/L green algae in the water samples  of Shark- El-Mansora station . After these analysis, It can say that our treated drinking water is safe and with high  quality.