SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I just purchased a lake house with a sprinkler system that feeds out of a lake. When the line leaves the pump, it goes straight up the lot and t's up to each sprinkler head with a valve below the head. Every sprinkler head is about 12" above ground. I want to get rid of the above ground sprinkler heads and replace with pop ups. How can I redesign my lines so I can replace with pop up sprinkler heads and underground valves.