In the last week I had two leak detection jobs. They both have HDPE pipe. What I did was I cut the water line and fed an electricians fish tape down the pipe. Then I energized that so I could locate the pipe with my Ridgid Scout. I marked on the ground where the pipe ran with depth markings, and then hooked it back up.
On the first job the pipe was outside the home, running under asphalt and concrete the entire way. There were no signs of water anywhere, the line was run between 3' and 5' deep, and the meter showed the leak was well over a gallon a minute. I walked on top of the line with my Goldak leak detector and couldn't hear anything. Getting frustrated, I started drilling 5/8" x 18" deep holes every few feet to see if anything came back wet, but nothing did. Then I started to push all thread into the holes to see which ones went down deeper then I drilled.
I was able to push the all thread down 5' in one hole, and the dirt looked like it could have been wet. I drilled a few more holes in that area, shoved the all thread back down, and listened to it with the Goldak. I finally was able to hear water flowing. Ended up tearing up the asphalt and digging down 5 feet, and was pretty close to the leak. Got it fixed and all was well.
I did the second one today. A new development that has the lines from the meter to the home run with HDPE. Traced this line out and find that it doesn't run straight from the meter to the main shut off and PRV in the garage, instead it is run in the same trench as the sewer. So what should have been a roughly 60' straight run is instead a 110' run under most of the house. I didn't have the Goldak on the truck today, so I am going back to the job on Thursday to locate where the leak actually is.
My question is how would you tackle these leaks? My way works, it just seems to take a really long time. I'm wondering if there isn't a better way that I'm missing.