To save on capital investment and operation cost it is often cost effi¬cient to split the water into two levels at this point. One line is multi-usage water for cleaning, washing and toilet use while the second line is pure drinking water.

Humans are suppose to drink at least two to three litres of water every day yet our average consumption ranges between 80 and 160 litres assuming we have assess to running water inside the place we live. The ration between drinking water and multi-usage water consumed is therefore approximately 1:40. Therefore it makes sense to have two categories of water.