For the Heritage quest The Essence of a Prophet (DoV) [Edgewater Drains level 3(bottom)] Even though the quest update symbol looks like it is in the first set of stairs leading down to level 2, pass by that and go all the way to the bottom of those stairs. Cross the room you end up in and there will be a second set of stairs leading down to level three. The room at the bottom is filled with water, but you only have to swim for a short distance. No water breathing needed.
