How do you find an underground leak in a 1000 foot underground PVC pipe?

Answer 1

You need to contact a professional leak detection company. We used Leak USA to find our leak on a 2400 foot PVC water line. When the contractor dug down to the pipe, the leak was exactly where they said it would be! I was totally amazed how accurate they were. Please do yourself a favor & do some research on the internet before hiring a contractor. Ask for references first. We learned this lesson the hard way. The first company we hired turned out to be a retired shoe salesman & his grandson who had decided to buy some tools & go into business together. They had no idea about Plumbing & couldn't find our leak. The older gentleman never got out of his van & the grandson kept telling us to dig here & dig there. When they couldn't find our leak they told us that this was a tough one & that we should try someone else. Luckily an engineer was working on another project on our property & they told us about Leak USA finding underground steam leaks & that this water line should be no problem for them. The engineer was right!

Good luck finding your leak & I hope that you find an experienced professional.

ANS#2If you are determined to do it yourself, you dig at the halfway point and cut and cap both ends. Apply air pressure to both ends and see which end leaks pressure. Once you find the end that leaks, dig halfway down on that...repeat the air pressure check. Narrow it down that way and soon you'll end up digging a short trench and finding the leak. It will take you about 8 holes and a trench:

1000'/2, 500'/2, 250'/2, 125'/2, 62.5'/2, 31.25'/2, 15.625'/2, 7.8125'...dig the trench.

Of course, this presumes that you know exactly where the line is running.

This also presumes that you haven't seen any obvious signs of the leak such as unusually green grass or mud holes. You might also drive rods into the ground at the same distance apart at the same depth along the length on either side of the pipe and check the soil conductivity with an ohm meter. Where you find high conductivity, you have found your leak. You could also borrow a UV camera and check the temperature difference along the line. A temperature change can pinpoint the leak.

Check the cost of what you are doing against the cost of trenching in a new line. You can rent a Ditch Witch for a lot cheaper than an expert leak detector and PVC is cheap.

Answer 2

You walk the pipe and look for wet spots.