The minimum recommended conecntration of free chlorine (mg/L) in drinking water at the end of 1 hour is -
Recommended contact period of free residual Chlorine in water : 1 hour Level of free residual chlorine (FRC) recommended : Water type Residual chlorine level (Recommended) Contact period Drinking water >0.5 mg per litre (ppm) 1 hour Water bodies, post disaster >0.7 mg per litre (ppm) 1 hour Swimming pool sanitation >1.0 mg per litre (ppm) 1 hour Ref: Park 25th edition Pgno : 752
0.1
0.5
1
1.5
Environment and health