Quest name: The Poisoned Water Supply
Objective: Cleanse the underground spring.
Quest trigger: Pepin the Healer (Tristram)
- The underground spring can be found by going into a door located southwest of the second level of the Cathedral, which leads to a dark passage.
- The door to the dark passage will be locked if you did not initiate the quest with Pepin.
- Killing the unique monster near the underground spring will cleanse it.
- Talking to Pepin after cleansing the spring will end the quest, and merit you a unique item, the Ring of Truth.