Yes, underground water pipes have to go in below the frost line - they are down around 4" here. The soil here is so rocky (nasty jagged dolomite packed in solid) that in addition to a backhoe I needed a jackhammer. Put sand in the bottom, then a layer of hay, then the water and electric, then more hay, then sheets of insulation board, then filled it back in. A big job, but so much labor saved - hoses in the winter are really tricky. Even a heated hose, if allowed to freeze, can split open in very cold weather. We used to run 200' of hose out to fill the horses' 150 gallon water trough, then reel it all back in and store it in the garage. Now we are down to a 25' hose from the hydrant to the trough every 3-4 days, and the chicken waterers can be filled from the hydrant (it does look like a pump handle, but you don't actually have to pump it, just raise the handle).
My plumber neighbor hooked the water line (2") up to the water line from the well just before it runs into the pressure tank. The first time I turned it on the water came out like from a fire hose - the hose took off spraying all over, chickens ran squawking, horses bolted for the back field, I got soaked catching it. Great pressure from the well! Takes about 10 minutes to fill a 150 gallon tank (took about 40 with the hose).
Insurance didn't cover much of cost to replace, so we haven't yet.
