For that I would find a local building inspector in a nearby city (where permits are required) and ask what would be required there. Type of line, depth of burial, and any other requirements. Then do what they say.
Around my area, the building inspectors have certain hours where you can go and ask them questions.
My thinking for doing this is that there are different areas, different weather conditions, different ground conditions, etc. And the "locals" would know about any problems typical to your specific area.
Maybe the ground is very rocky in a certain area and these rocks can puncture tubing, so they would require sand or a certain tubing?
Or maybe the ground freezes in that area and they might require a certain tubing or burial depth?
Or somewhere like Arizona it gets to be so hot things will melt! A problem local to that area.
Who knows? Anyway if you ask a local, you will get the best advice for your specific area.