Drinking water is water that is safe to drink. If water is taken from a river, it will contain many pieces of soil and other materials suspended in it. These have to be strained out using filters.

That is easy to do. It is much more difficult to get microbes and any harmful dissolved materials out of the water.

The water has to go through a number of stages where ultra-violet light and chemicals are used to kill microbes, and stages where any harmful chemicals are neutralised.

We may take drinking water for granted, but cleaning the water properly helps us stay healthy and it is one of the most important things we do.