Which one of the following is the level of residual free chlorine recommended for swimming pool water disinfection?
0.5 mg/litre
0.8 mg/litre
1 mg/litre
5 mg/litre
Chlorination is the most widely used method of pool disinfection. Various workers have stated that continuous maintenance of 1mg/litre(1ppm) of free residual chlorine provides adequate protection against bacterial and viral agents. Park's Textbook of Preventive and Social Medicine, 25th edition, Page No. 788
Environment and health