Municipal works are to code when both municipality and contractor are in agreement.here the owner or developer is responsible for the feed line between municipal at the street to the house. cost primarily shoved everyone on to pvc.
for the most part temp changes and ground movement pretty much dictates the material. copper would often shear with the freeze thaw cycles and we have enough trouble with the mains as it is.
edit : over 6 yrs we had our mains break 3 times. the entire block has been dug up in pieces yr over yr. the city might do the whole thing over again and replace it all.