I just completed Waterworks. It was the most difficult thing I have done in-game. I went in with four other wizards, but then at the beginning one had to leave. So the three of us continue on, until the last valve, when another person has to leave. It is just me and one other lv. 63 pyromancer. I wanted to abandon it and leave, but he showed me some tricks he had learned. So we got to the last fight, just me and him, and we started the fight. It was the hardest and longest fight I had ever been in. I sad there for +40 minutes, muddling through the battle, and we won. I was about halfway through 60, and I got 49,000 exp from the battle, not the quest. I didn't even get the mastery amulet I was hoping for.
DON'T UNDERESTIMATE THE WATERWORKS!