[dalereed]

Properly installed copper won't corrode or be effected by electrolisis either.

It's legal to use plastic for mains in California up to the structure but must be changed to copper or galvanized going into the house.

Unless plastic mains are covered with a concrete slurry prior to burrying they are still too easially broken, i've had to repair too many of them.

[Carry_Okie]

We used sand in a sandstone ditch. No problems. As far as the concrete goes, well, unless you have a gopher problem when it cracks you'll wish you never had. Gophers can be foiled by going to 2". It might be fun to try setting a schedule 40 line in a coex polyethylene conduit. That might work even better.

Our well is hanging on 450' of 1" threaded schedule 80. The installer is well known for reliable systems. He won't use anything else. The big problem with plastic is grounding all the valves in the system. IMHO, there should be a tapped hole in every metal valve for attaching a ground wire. Fire hydrants and big gate valves (4") are especially bad.