Although different wastewater treatment methods were developed but none of them could guarantee viral removal and inactivation. That made reuse of treated wastewater a cause of viral transmission. Here we evaluated the effect of increasing pH values of wastewater on adenovirus, Herpes simplex virus type 1, rotavirus , coxsackievirus B and Influenza A virus infectivity. On inoculating each virus at a time in distilled water with pH range 8-13, results showed that viral inactivation was directly proportional to increasing both pH and incubation time and that complete inhibition of all tested viruses was achieved upon co-incubation for 1 hour with water at pH12. Same conditions also caused complete inactivation of the same viruses inoculated in sterile-autoclaved waste water. Viral inactivation due to increasing pH value to 12 was also achieved in field samples. Physico-chemical properties of wastewater samples were characterized before and after increasing pH to 12. Results showed that increasing pH caused decrease in heavy metals as well as sulphate, phosphate, bicarbonate concentrations which also suggest pH increase as mean to reduce chemical pollutants of wastewater.