Yes. We drink water. Our food drinks water (plants and animals). Water supports vast ecosystems, that we need for important things like, oh, air. If water is polluted in any way that impairs any of those functions, we're in trouble.

depends on what is considered water pollution. Mainstream science and a consensus consider CO2 a pollutant now even though that trace gas is essential to nearly every form of life on earth.

Duh. It harms aquatic life and in turn can harm us. It reduces biodiversity, limits the food supply, and also the toxicity can react with coastlines to cause further destruction. So yeah... of course

Yes. Try drinking toilet water

yea you can die from it

Yes because if Earth water gets fully polluted we will die an most likely Earth will too