Question

How does drinking water get contaminated

Answer 1

The drinking water will get contaminated by throwing waste in the water.
By allowing Industrial chemicals into water.etc

Answer 2

water is an essential source for life on earth.without water nothing can survive in  this world.water will get contaminated because of human activities.such as:-1.leakage of sewage into river waters,2.leaving wastes of factories into river waters,3.throwing rubber wastes,plastics into river waters.in this way drinking waters[rivers]get contaminated.