This weekend I am running a new water line to the barn. The water line exits the pump room about 12″ above the slab, through the basement concrete wall to a three foot wide passage 20 feet along a 8 foot high retaining wall. I can not excavate the footing of the retaing wall down 24 inches to the frost line. Do I use pipe insulation protected by 4 inch pvc pipe? Do I use heavy wall copper pipe and heat tape (that can fail)? I plan on using black poly 160 psi and a bed of sand for the line that can be buried down 24 inches. I did search the achives.
Thanks guys in advance.