Unless you live in Iceland, chances are you are drinking water that is far from pure. However, a lot of us have it VERY good considering we can drink some tap water without boiling it or walking miles to find a lake.
If you are looking to purify your water, Japanese Kishu Binchotan is a superior quality white charcoal for doing so. "White charcoal is naturally activated through a controlled burning process done by hand and based on traditional Japanese methods. Binchotan soaks up chlorine and other unpleasant tastes from drinking water while releasing natural minerals into it. Binchotan has an alkaline effect, softening the water and improving the overall taste."
Found at Merchant no.4