You can go to PPI to find what they promote as all the advantages of hdpe pipes. However, hdpe pipe systems are different than ductile iron with regard to many issues (obvious and perhaps non-obvious) involved in the construction, operation, and maintenance of "reticulation" systems. Many of these issues are explained, as well as direct comparison testing between the piping materials with regard to different features and strengths (I think most or all of the testing referred to in the DIPRA publications were either performed or witnessed by third-parties) in the publications at
under the heading, "Why Ductile Iron Pipe is Superior to HDPE Pipe". I would recommend learning as much about these issues from all available information, as well as perhaps talking with some folks who have had to deal with the piping, before making changes.
