Oliver Cannell, a student currently studying environmental sciences at the University of East Anglia in the U.K., asked me for a definition of sustainable consumption. I gave him one, and in the writing of it realized that we have, in addition to a constant input of energy from the sun and time from the Universe, an ever-increasing resource in terms of human ingenuity.
We've been transporting water for all of recorded history, and along the way have discovered lead poisoning and hydraulics, created new methods of organizing people and making people pay for something that is inherently free, and other marvels. We've used materials science and social science to solve the problems we encounter.
A lead pipe is completely recyclable, but the side effects of water transported in lead are hard on folks. An steel pipe will rust; dipping it in zinc creates a material that when scratched will heal itself. Unfortunately, the zinc is a contaminant if you want to recycle the steel.
Recycling wasn't as important 150 years ago. Delivering clean water was. Now we believe recycling is important, too. With the power of human ingenuity we'll come up with another material that is "better" than hot-dipped galvanized pipe (or PVC pipe, or ABS, or any of the other non-recyclable materials) for delivering water.