I recently found out that my water main under the driveway, of course, was leaking. I paid to have someone detect where the leak was and jack hammered and dug to get to the leak. I found the leak on a 1 foot piece of black ABS Sch 40 piping connected to white PVC Sch 40 pipe on each side. What are the reasons why this section leaked? I heard that there is no glue that can join the two different types of material and that Black ABS pipe is typically used for sewer lines. Is that true?

-Mark

Mark, you are correct, black ABS pipe is not for use as a water main (it’s not made to withstand much pressure), it should only be used as drain and sewer piping (carries away wastewater under no pressure). Most plumbing codes don’t permit ABS pipe to be glued to PVC, though you should check with your local inspector. You should use a transition coupling, a neoprene rubber sleeve that fits over the end of each pipe. It’s then held tightly in place with a stainless steel metal jacket and clamps. Couplings are labeled to show which type of pipe each end can be attached to. Perhaps this ABS pipe was used as a sleeve and your water pipe was actually inside, it is very unusual that ABS pipe was used as a water service.

-Brian