Southside plumbing replaced sprinkler valve that had failed and was allowing water through, which caused a split pipe on he backflow inside the home. Removed split pipe and replaced hose bib that was under the backflow along with new pipe. We also added anew drain off valve below the hose bib so that homeowner can drain down any water that gets trapped in the line. Tested for leaks, no all our work was good. There was a slow drip on the first union on the backflow outside, which the homeowner had just replaced. I tried to tighten it, but it did not stop the drip. Recommended to homeowner to undo the union, and add more, Teflon, tape, and re-tighten and test for leaks.