Question

Can Earth's water ever be clean and pure again?

Answer 1

There is  no such thing as pure water, when you  buy bottled water you think you're buying pure water but it's the same water.

I'm not going into the scientific facts here but the truth is 'pure' water does not exist because that means the water will have NOTHING in it which means they will have to remove the natural minerals and then the water will interact with any organic materials the water encounters, including air and plastic. 

But the water is clean and healthy to drink. Just not pure.

Answer 2

There is a lot of pollution, dirts and organism inside water. This tells us that water is not pure. Hence, we can make it drinkable and suitable to the mouth. Not by adding chemicals because chemicals can make it not good or drinkable and can cause harm to the human body. We purify water by filtering it with the tools required. Hope this helps! :)