Reply To: Joined Copper Pipe Under Concrete

[TheLocalPlumberParticipant]

Per code all copper joints underground are to be silver soldered. If it has not been properly soldered it does not mean it will fail. It probably will not pass inspection.
I personally do not think you are taking a chance leaving it as is.
Good Luck,
Bill
The Local Plumber
Tustin, California http://www.TheLocalPlumber.com