Taintless Water of Irr is Epic with a total supply of 997
812 left (of 997) - Known to be found in Haunted Catacomb, and Shattering Chamber
The densely forested hills that surround the city of Irr in the north of the Isle of Mellith contains what some claim to be the purest streams of untainted water in the world.
Knowing this explains why some go to the length of navigating through the bear inhabited forests to acquire this pristine water, for as it is commonly said by alchemists, 'The purer the water, the purer the alchemy!'.
That sounds simple enough.