IMHO, I think a lot of people have missed the point to this movie. What it's really about is how much trouble you can get in if you don't take care of your plumbing properly. Remember that Eve comments in her diary that Ed has been acting strangely for quite a while - this is clearly due to the unbearable burden of his plumbing problems which he is not able to handle, and which eventually drive him crazy. The murder of his wife, her unborn child, all the hallucinations, and finally the attempted suicide with all those pills - all because he didn't consult a licensed plumber in time. And on one level, of course, Ed knows this, and it is his tremendous guilt at not taking proper care of his pipes that drives him over the edge. He even anthropomorphizes his plumbing, resulting in all that blood pouring out of everywhere. (This analysis may even give one reason to reevaluate what's really happening in "The Shining".) Never have I seen a movie that so effectively drives home the importance of good plumbing maintenance.
This movie should be a warning to us all.
This movie should be a warning to us all.