Hi Was wondering if anyone could give me some information on running a frost free waterline from one building to another. The frost line is 42". It is going from the house existing water lines, copper pipes, to a 100' greenhouse I just put up, 200 feet away. A frost free hydrant will be installed in the greenhouse, with a one way check valve. What is the best material to use for the line itself? Copper? PVC?

Thank you for any assistance.