Drinking Water Analysis

We have around 60% water in our body. i.e 2/3 rd part of human body made up of water. what if the water we are drinking is contaminated? Over 3 million people die (majorly because of Diarrhea) every year because of water pollution. To make sure that water we are drinking is pure and contains no bacteria and harmful metals Drinking water analysis is necessary. We have heard Precaution is better than cure since our childhood it is true in this case also.