They don't stand a chance against the things coming out of the portal in your basement, right, o mighty destroyer of worlds? This is all just a trap for The Man, isn't it?
Seriously, there could just have been power problems, she had a rally bad few weeks before this, and killed herself via drowning in the cistern, and then an unassuming maintenance worker closed it, not expecting shit, and not seeing th body. Besides, city water tastes like shit to begin with, I wouldn't be able to tell the difference between corpse water and water tower tankage myself... The key is what happened before this, and then maybe I'll be able to kinda sorta paint my own opinion.