Tokyo, Japan
The main river Tonedo River and the Tama and three reservoirs supply most of Tokyo's drinking water.

Item Water Quality Standard Value
Copper 1.0mg/L(Max)
Nitrate 10mg/L(Max)
Fluorine 0.8mg/L(Max)
Lead 0.05mg/L(Max)
Coliform 0.06mg/L(Max)
Uranium 0.002mg/L(Max)
Chloral Hydrate 0.03mg/L(Max)
Bromoform 0.09mg/L(Max)
Chloriform 0.06mg/L(Max)
Trihalomethanes 0.1mg/L(Max)
Dichlorobromoethane 0.004mg/L(Max)
Dibromocholoromethane 0.1mg/L(Max)