The first layer: chemical cleaning

Before entering this layer, I emphasize that in my opinion, despite everything that will be said here, the human body has an amazing ability to clean
poisons, and to do this he asks for satiety.
Therefore, for me, the saturation of the body is more important than avoiding drinking because of the dirtiness of the water.
Why is chemical cleaning necessary?
Our drinking water as consumers has a lot of dirt, metals and toxins

The decrease in the quality of tap water because of global pollution
environment over time has become a major social problem, thereby concern
over tap water quality has led to the expansion of water filtration plants and
had encouraged the marketing of filtered water, including filtered alkaline
water