[TheEplumber]

Joe, or others, regarding using pex or polyethylene pipe. Do you use compression fittings under ground? Are they reliable enough to bury?

We use 160lb. or better poly in our area.
When connecting to pvc I use MIP adapter on the pvc- female threads are known to crack.
After the pvc adapter, it's bass and poly. If you want to spend the money go with pack fittings. They'll last for ever and are easy to work with.
Or you can go the cheap route and use galv. barbed fittings and hose clamps(2 on each end)

Note: I don't think all brands of Pex fittings are approved for bury- double check first

 

[TheEplumber]

Poly can have 2 OD's - iron pipe(IP) or copper tube (CTS) make sure the pak you get is the right poly OD
They also need an insert to go inside the poly so it doesn't collapse when you compress down the nut.
They work on the same principle as a nut and ferrule joint except the ferrule is not brass- rather a rubber of sorts.

IMO, they beat the insert and ss band route, but they cost more. Both are approved in my area.