Don't you hate making water for a raid? Over and over clicking that one button and drinking, evocation, drinking... boring, isn't it? I have a solution!
If you have Mana Absorbtion (Restores 5% mana every time you fully resist a spell, requires 5 points in arcane) get a friend who has a level 30 caster (30 because you can resist a lot and they can cast a lot).
Go outside the city and dual. Have your friend cast Rank 1 of whatever spell and every time you resist you get 5% mana, for me that is about 350.
You'll still run out of mana but you'll also get in a few more stacks water and it dosen't take long at all to fill back up.