Greetings,

Why are you not allowed to solder copper pipe which is going to be
installed underground? I want to be very clear what question I am
asking. I am not asking for 10 responses stating that I must not
solder copper pipe to be used underground or why don't I just use a
compression fitting. I know that. I am asking why I am not suppose
to? I am not asking for the reason "because someone said so". I am
asking about the underlying reason.

Thank you very much for your time and energy,
William