@umbra21 - It's a really difficult call, unfortunately. Water is a limited resource in a lot of places.
Public private partnership investment can work sometimes but more often than not it doesn't seem to, or it only works in some ways. Unfortunately, it doesn't seem to be going anywhere anytime soon.
I think that if the companies involved are regulated correctly it can definitely work. Unfortunately, in developing countries the government itself is often also corrupt so you can hardly expect the businesses to be paragons of virtue.