Water thief

The water thief is, as his name suggests, a water thief in Vault 13

Quests
Find the Water Thief: When confronted, the water thief will give the same dialogue as "The Sleepy Vault Dweller," stating he had a nightmare and was worried about the vault's water supply. When the Vault Dweller asks to search him the water thief becomes defensive and states he is innocent. Upon intimidation, the water thief will oblige and the screen will go black, the thief will be gone and the Vault Dweller will be rewarded for completing the quest.

Appearances
The water thief appears only in Fallout.