This spell purified a body of water, removing all poisons, toxins, salt, or any other unpleasant or armful effects. This spell could even turn a magical potion into regular water.Wizards with more power were able to affect larger bodies of water.
Once cast, the effects of the spell were permanent for the target body of water. However, this did not prevent the water from being contaminated again in the future.
The reverse of this spell, pollute water, had the exact opposite effect, contaminating the water with a strong poison.
This spell required a handful of sand tainted with a drop of the caster' blood to cast.