Irrigation pipe
 

I was digging a hole in my backyard to plant a tree maybe 3 feet away from the foundation. Out of the blue I saw a black pipe sticking out. It's a black PVC pipe 1/2" and written irrigation on it. The thing is I can't find the other end!!! I should mention I have a sprinkler system and that I moved into that house in January so I have no clue how the system is ran. How can I trace where that pipe comes from and go to??? I tried air and water but doesn't seem to activate any of the sprinkler heads!!!!!

Could just be a remnant from an older version of the sprinkler system you have.