You definitely should not have any leaking.  I suggest you call a plumber to come look at the issue.

Hi John, 

Turn on your sprinklers for the zone your leak is on and let it run. The area where the leak is will cause the ground around it to be soaked and water logged more so than any other area. There is your leak.

Good luck!

If you are leaving the house, you definitely want to shut the water off to the house, in case the water line bursts. Otherwise, if you can find the frozen area, you can take a hair dryer to the spot to slowly thaw the pipes. Don't het the pipe quickly, as this will most likely cause the pipe to burst. Just always be ready to shut the water off to the entire house and have a bucket near. Good Luck.