Line the trench for a new water line?

I'm having an addition built and asked about having a new water line put in. The neighbors say that their's last about 20 years before needing leaks repaired due to tree roots, old PVC leaking, etc. The contractor says it's my choice and that it will cost $1500 if I want it. The house is 100 feet from the street.

I was thinking of two ideas.

1. Can you dig a trench and line it with concrete to prevent tree roots from coming in? How deep are water lines usually buried in Western Washington, 3 feet?

2. Can you put in the middle of a long driveway and cover it up with metal plates? The driveway obviously has no trees. I think the metal plate idea is impractical.

pipe

Use a copper line and you do not have to worry about it, and it should NOT cost $1,500.00.